How to resolve typescript errors in custom theme in Material UI 5?

We have palette.ts which contains all color properties in palette variable and exported. And we imported palette.ts in themeProvider.tsx and used. But we are getting typescript error due to custom properties as following picture. Is it any way to define the type for custom properties.

palette.ts

import { alpha } from '@mui/material/styles';

const palette = {
  common: { black: '#000', white: '#fff' },
  primary: { ...PRIMARY },
  secondary: { ...SECONDARY },
  info: { ...INFO },
  success: { ...SUCCESS },
  warning: { ...WARNING },
  error: { ...ERROR },
  grey: GREY,
  gradients: GRADIENTS,
  chart: CHART_COLORS,
  divider: GREY[500_24],
  text: { primary: GREY[800], secondary: GREY[600], disabled: GREY[500] },
  background: { paper: '#fff', default: GREY[100], neutral: GREY[200] },
  action: {
    active: GREY[600],
    hover: GREY[500_8],
    selected: GREY[500_16],
    disabled: GREY[500_80],
    disabledBackground: GREY[500_24],
    focus: GREY[500_24],
    hoverOpacity: 0.08,
    disabledOpacity: 0.48,
  },
  custom: {
    iconBorderRadius: 1,
    iconBorderRadius2: 0.5,
  },
};

export default palette;

themeProvider.tsx

import { createTheme, CssBaseline } from '@mui/material';
import {
  StyledEngineProvider, ThemeProvider as MUIThemeProvider
} from '@mui/material/styles';
import React, { useMemo } from 'react';
import componentsOverride from './overrides';
import palette from './palette';
import shadows, { customShadows } from './shadows';
import typography from './typography';

export default function ThemeProvider({ children }) {
  const themeOptions = useMemo(
    () => ({
      palette,
      shape: { borderRadius: 8 },
      typography,
      shadows,
      customShadows,
    }),
    []
  );
  const theme = createTheme(themeOptions);
  theme.components = componentsOverride(theme);

  return (
    <StyledEngineProvider injectFirst>
      <MUIThemeProvider theme={theme}>
        <CssBaseline />
        {children}
      </MUIThemeProvider>
    </StyledEngineProvider>
  );
}

Usage typescript error