Cross, who starred on the cult TV comedy, "Arrested Development," confessed to the impulsive act in the March issue of Playboy magazine. He has reportedly told the story before, but the Playboy interview was the first time he divulged all the details.
"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," Cross said. "It wasn't like I got high. The jolt was similar to licking an empty espresso cup."
Cross, who admits to experimenting with a wide range of drugs, including crack cocaine, said his goal at the 2009 event was not to get high.
"It was just about being able to say that I did it, that I did cocaine in the same room as the president," he said. "I'm not proud of it, nor am I ashamed of it."
He said his only regret from the experience is getting his girlfriend, "The Sisterhood of the Traveling Pants" 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," he said. "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."