The Sideways star portrays a horny U.S. attorney who is determined to prosecute a hedge fund titan, played by Damian Lewis, on the upcoming financial drama, and the premiere episode features Giamatti tied up in a raunchy sex scene, with a ball gag in his mouth.

The actor reveals producers recruited an expert to tie him up, but the way the rope was tightened around his body actually put him to sleep.

"It was really interesting, they brought in a special guy to tie me up," he explains to U.S. talk show host Stephen Colbert. "I never saw the guy on the set again, just this one time! He was really trussing me up and he was dead serious about it...

"I was like, 'Who the hell is this guy?' They got me genuinely trussed up; the more you move, the tighter it gets! It was extraordinary because my reaction to it was really surprising - I fell asleep!

"I had a warm washing feeling go over me and I just dropped off. They had to keep waking me up between takes! They were like, 'Hey, buddy! Hey, hey, hey! We're gonna shoot, buddy!' It was crazy. It was the weirdest reaction, I didn't expect that."