John Legend attends the Comedy Central Roast Of Donald Trump at the Hammerstein Ballroom on March 9, 2011 in New York City.

*Last month he was in the audience for Comedy Central’s Roast of Donald Trump. [See photo above]. Today, John Legend is getting in a few digs of his own, calling the real estate mogul’s obsession with President Obama’s birth certificate “racist.”

“He needs to stop saying that racist bulls**t birther s**t,” Legend told Vulture last night in New York City. “Quote me please. He should be ashamed of himself. It’s awful, really.”

Trump, currently promoting his NBC show “Celebrity Apprentice,” makes headlines every time he openly questions President Obama’s place of birth – and he does it every chance he gets, revealing this week that he hired a private investigator to fly to Hawaii and poke around in Obama’s past.

As previously reported, Bill Cosby expressed his frustration with Trump during a Thursday appearance on “Today.”  Asked about Trump’s presidential ambitions, Cosby said “the only thing he’s running is his mouth.”

“Oh, please, with Donald Trump,” Cosby continued. “Take him home with you. He’s full of it.”