Comedienne Joan Rivers revealed she once ditched a joke about First Lady Michelle Obama from her stand-up routine - because she feared she'd be accused of racism.

Recalling the wisecrack to shock Jock Howard Stern, the comedy legend said: "We used to have Jackie O now we have Blackie O!"

The audio can be heard here on RadarOnline.com.

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Rivers wrote the quip about President Barack Obama's wife in reference to her fashionable dress sense and comparing her to former First Lady Jackie Onassis.

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"I thought it was a funny complimentary joke when she first came (to the White House)," the 77-year-old comedienne told Stern.