The Arrested Development star told Playboy that he used the drug when he was just "65 feet" away from Obama at the 2009 White House Correspondents' Association dinner at the Washington Hilton.
"It wasn't even that much cocaine. It was literally the size of, I don't know, a tick," Cross explained. "It was a tiny granule of coke that I put on my wrist and said, 'Watch this. I need a witness'. And then I ducked under the table and did it. It wasn't like I got high. The jolt was similar to licking an empty espresso cup."
He went on to say: "It was just about being able to say that I did it, that I did cocaine in the same room as the president. I'm not proud of it, nor am I ashamed of it. My one regret is that I got my girlfriend [actress Amber Tamblyn] in trouble by association.
"I was her date, her plus-one, and she got dragged through the mud because of what I did. She had nothing to do with it. She didn't know I was going to do it. And because of that she'll never be invited to the White House again. That's not cool."
Cross also spoke about the Occupy Wall Street movement and revealed why he's reluctant to publicly support the protestors.
"I have mixed emotions, and I did from the very beginning," the actor said. "My fear, which is born out of experience, is that the majority of the people will be well-meaning but ultimately feckless and perhaps may do more harm than good. I hope I'm wrong, but it feels as if not a whole lot is going to come of this."
Cross recently revealed that he has "high hopes" for the Arrested Development reunion miniseries and film, but still isn't completely sure the project will get off the ground.
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Watch clips of David Cross in Arrested Development below: