diff --git a/x-pack/plugins/lens/public/xy_visualization/color_assignment.ts b/x-pack/plugins/lens/public/xy_visualization/color_assignment.ts
index 1e00d821d9b3..30238507c356 100644
--- a/x-pack/plugins/lens/public/xy_visualization/color_assignment.ts
+++ b/x-pack/plugins/lens/public/xy_visualization/color_assignment.ts
@@ -8,9 +8,10 @@
 import { uniq, mapValues } from 'lodash';
 import type { PaletteOutput, PaletteRegistry } from 'src/plugins/charts/public';
 import type { Datatable } from 'src/plugins/expressions';
+import { euiLightVars } from '@kbn/ui-shared-deps-src/theme';
 import type { AccessorConfig, FramePublicAPI } from '../types';
 import { getColumnToLabelMap } from './state_helpers';
-import type { FormatFactory } from '../../common';
+import { FormatFactory, LayerType, layerTypes } from '../../common';
 import type { XYLayerConfig } from '../../common/expressions';
 
 const isPrimitive = (value: unknown): boolean => value != null && typeof value !== 'object';
@@ -20,8 +21,11 @@ interface LayerColorConfig {
   splitAccessor?: string;
   accessors: string[];
   layerId: string;
+  layerType: LayerType;
 }
 
+export const defaultThresholdColor = euiLightVars.euiColorDarkShade;
+
 export type ColorAssignments = Record<
   string,
   {
@@ -37,13 +41,15 @@ export function getColorAssignments(
 ): ColorAssignments {
   const layersPerPalette: Record<string, LayerColorConfig[]> = {};
 
-  layers.forEach((layer) => {
-    const palette = layer.palette?.name || 'default';
-    if (!layersPerPalette[palette]) {
-      layersPerPalette[palette] = [];
-    }
-    layersPerPalette[palette].push(layer);
-  });
+  layers
+    .filter(({ layerType }) => layerType === layerTypes.DATA)
+    .forEach((layer) => {
+      const palette = layer.palette?.name || 'default';
+      if (!layersPerPalette[palette]) {
+        layersPerPalette[palette] = [];
+      }
+      layersPerPalette[palette].push(layer);
+    });
 
   return mapValues(layersPerPalette, (paletteLayers) => {
     const seriesPerLayer = paletteLayers.map((layer, layerIndex) => {
@@ -111,6 +117,13 @@ export function getAccessorColorConfig(
         triggerIcon: 'disabled',
       };
     }
+    if (layer.layerType === layerTypes.THRESHOLD) {
+      return {
+        columnId: accessor as string,
+        triggerIcon: 'color',
+        color: currentYConfig?.color || defaultThresholdColor,
+      };
+    }
     const columnToLabel = getColumnToLabelMap(layer, frame.datasourceLayers[layer.layerId]);
     const rank = colorAssignments[currentPalette.name].getRank(
       layer,
@@ -133,7 +146,7 @@ export function getAccessorColorConfig(
     return {
       columnId: accessor as string,
       triggerIcon: customColor ? 'color' : 'disabled',
-      color: customColor ? customColor : undefined,
+      color: customColor ?? undefined,
     };
   });
 }
diff --git a/x-pack/plugins/lens/public/xy_visualization/expression.tsx b/x-pack/plugins/lens/public/xy_visualization/expression.tsx
index bc80b4569977..c4315b7ccea8 100644
--- a/x-pack/plugins/lens/public/xy_visualization/expression.tsx
+++ b/x-pack/plugins/lens/public/xy_visualization/expression.tsx
@@ -836,7 +836,6 @@ export function XYChart({
         <ThresholdAnnotations
           thresholdLayers={thresholdLayers}
           data={data}
-          colorAssignments={colorAssignments}
           syncColors={syncColors}
           paletteService={paletteService}
           formatters={{
diff --git a/x-pack/plugins/lens/public/xy_visualization/expression_thresholds.tsx b/x-pack/plugins/lens/public/xy_visualization/expression_thresholds.tsx
index 171e2f1cfba9..d9c0b3670263 100644
--- a/x-pack/plugins/lens/public/xy_visualization/expression_thresholds.tsx
+++ b/x-pack/plugins/lens/public/xy_visualization/expression_thresholds.tsx
@@ -9,23 +9,21 @@ import React from 'react';
 import { groupBy } from 'lodash';
 import { EuiIcon } from '@elastic/eui';
 import { RectAnnotation, AnnotationDomainType, LineAnnotation } from '@elastic/charts';
-import type { PaletteRegistry, SeriesLayer } from 'src/plugins/charts/public';
+import type { PaletteRegistry } from 'src/plugins/charts/public';
 import type { FieldFormat } from 'src/plugins/field_formats/common';
+import { euiLightVars } from '@kbn/ui-shared-deps-src/theme';
 import type { LayerArgs } from '../../common/expressions';
 import type { LensMultiTable } from '../../common/types';
-import type { ColorAssignments } from './color_assignment';
 
 export const ThresholdAnnotations = ({
   thresholdLayers,
   data,
-  colorAssignments,
   formatters,
   paletteService,
   syncColors,
 }: {
   thresholdLayers: LayerArgs[];
   data: LensMultiTable;
-  colorAssignments: ColorAssignments;
   formatters: Record<'left' | 'right' | 'bottom', FieldFormat | undefined>;
   paletteService: PaletteRegistry;
   syncColors: boolean;
@@ -36,12 +34,11 @@ export const ThresholdAnnotations = ({
         if (!thresholdLayer.yConfig) {
           return [];
         }
-        const { columnToLabel, palette, yConfig: yConfigs, layerId } = thresholdLayer;
+        const { columnToLabel, yConfig: yConfigs, layerId } = thresholdLayer;
         const columnToLabelMap: Record<string, string> = columnToLabel
           ? JSON.parse(columnToLabel)
           : {};
         const table = data.tables[layerId];
-        const colorAssignment = colorAssignments[palette.name];
 
         const row = table.rows[0];
 
@@ -62,27 +59,7 @@ export const ThresholdAnnotations = ({
 
           const formatter = formatters[groupId || 'bottom'];
 
-          const seriesLayers: SeriesLayer[] = [
-            {
-              name: columnToLabelMap[yConfig.forAccessor],
-              totalSeriesAtDepth: colorAssignment.totalSeriesCount,
-              rankAtDepth: colorAssignment.getRank(
-                thresholdLayer,
-                String(yConfig.forAccessor),
-                String(yConfig.forAccessor)
-              ),
-            },
-          ];
-          const defaultColor = paletteService.get(palette.name).getCategoricalColor(
-            seriesLayers,
-            {
-              maxDepth: 1,
-              behindText: false,
-              totalSeries: colorAssignment.totalSeriesCount,
-              syncColors,
-            },
-            palette.params
-          );
+          const defaultColor = euiLightVars.euiColorDarkShade;
 
           const props = {
             groupId,
@@ -99,7 +76,7 @@ export const ThresholdAnnotations = ({
 
           const sharedStyle = {
             strokeWidth: yConfig.lineWidth || 1,
-            stroke: (yConfig.color || defaultColor) ?? '#f00',
+            stroke: yConfig.color || defaultColor,
             dash: dashStyle,
           };
 
@@ -179,7 +156,7 @@ export const ThresholdAnnotations = ({
                 })}
                 style={{
                   ...sharedStyle,
-                  fill: (yConfig.color || defaultColor) ?? '#f00',
+                  fill: yConfig.color || defaultColor,
                   opacity: 0.1,
                 }}
               />
diff --git a/x-pack/plugins/lens/public/xy_visualization/to_expression.ts b/x-pack/plugins/lens/public/xy_visualization/to_expression.ts
index 1996f918b675..b66f0ca4687b 100644
--- a/x-pack/plugins/lens/public/xy_visualization/to_expression.ts
+++ b/x-pack/plugins/lens/public/xy_visualization/to_expression.ts
@@ -13,6 +13,7 @@ import { OperationMetadata, DatasourcePublicAPI } from '../types';
 import { getColumnToLabelMap } from './state_helpers';
 import type { ValidLayer, XYLayerConfig } from '../../common/expressions';
 import { layerTypes } from '../../common';
+import { defaultThresholdColor } from './color_assignment';
 
 export const getSortedAccessors = (datasource: DatasourcePublicAPI, layer: XYLayerConfig) => {
   const originalOrder = datasource
@@ -334,9 +335,9 @@ export const buildExpression = (
                               arguments: {
                                 forAccessor: [yConfig.forAccessor],
                                 axisMode: yConfig.axisMode ? [yConfig.axisMode] : [],
-                                color: yConfig.color ? [yConfig.color] : [],
-                                lineStyle: yConfig.lineStyle ? [yConfig.lineStyle] : [],
-                                lineWidth: yConfig.lineWidth ? [yConfig.lineWidth] : [],
+                                color: [yConfig.color || defaultThresholdColor],
+                                lineStyle: [yConfig.lineStyle || 'solid'],
+                                lineWidth: [yConfig.lineWidth || 1],
                                 fill: [yConfig.fill || 'none'],
                                 icon: yConfig.icon ? [yConfig.icon] : [],
                               },
diff --git a/x-pack/plugins/lens/public/xy_visualization/visualization.test.ts b/x-pack/plugins/lens/public/xy_visualization/visualization.test.ts
index 8907db4954f9..8052b0d59321 100644
--- a/x-pack/plugins/lens/public/xy_visualization/visualization.test.ts
+++ b/x-pack/plugins/lens/public/xy_visualization/visualization.test.ts
@@ -347,9 +347,6 @@ describe('xy_visualization', () => {
           {
             axisMode: 'bottom',
             forAccessor: 'newCol',
-            icon: undefined,
-            lineStyle: 'solid',
-            lineWidth: 1,
           },
         ],
       });
diff --git a/x-pack/plugins/lens/public/xy_visualization/visualization.tsx b/x-pack/plugins/lens/public/xy_visualization/visualization.tsx
index 33cd01c8fda7..4e279d2e0026 100644
--- a/x-pack/plugins/lens/public/xy_visualization/visualization.tsx
+++ b/x-pack/plugins/lens/public/xy_visualization/visualization.tsx
@@ -448,12 +448,7 @@ export const getXyVisualization = ({
       if (!hasYConfig) {
         newLayer.yConfig = [
           ...(newLayer.yConfig || []),
-          // TODO: move this
-          // add a default config if none is available
           {
-            icon: undefined,
-            lineStyle: 'solid',
-            lineWidth: 1,
             // override with previous styling,
             ...previousYConfig,
             // but keep the new group & id config
diff --git a/x-pack/plugins/lens/public/xy_visualization/xy_config_panel/color_picker.tsx b/x-pack/plugins/lens/public/xy_visualization/xy_config_panel/color_picker.tsx
index 5a6458a4654d..516adbf585b9 100644
--- a/x-pack/plugins/lens/public/xy_visualization/xy_config_panel/color_picker.tsx
+++ b/x-pack/plugins/lens/public/xy_visualization/xy_config_panel/color_picker.tsx
@@ -13,9 +13,13 @@ import { EuiFormRow, EuiColorPicker, EuiColorPickerProps, EuiToolTip, EuiIcon }
 import type { PaletteRegistry } from 'src/plugins/charts/public';
 import type { VisualizationDimensionEditorProps } from '../../types';
 import { State } from '../types';
-import { FormatFactory } from '../../../common';
+import { FormatFactory, layerTypes } from '../../../common';
 import { getSeriesColor } from '../state_helpers';
-import { getAccessorColorConfig, getColorAssignments } from '../color_assignment';
+import {
+  defaultThresholdColor,
+  getAccessorColorConfig,
+  getColorAssignments,
+} from '../color_assignment';
 import { getSortedAccessors } from '../to_expression';
 import { updateLayer } from '.';
 import { TooltipWrapper } from '../../shared_components';
@@ -56,6 +60,9 @@ export const ColorPicker = ({
   const overwriteColor = getSeriesColor(layer, accessor);
   const currentColor = useMemo(() => {
     if (overwriteColor || !frame.activeData) return overwriteColor;
+    if (layer.layerType === layerTypes.THRESHOLD) {
+      return defaultThresholdColor;
+    }
 
     const datasource = frame.datasourceLayers[layer.layerId];
     const sortedAccessors: string[] = getSortedAccessors(datasource, layer);