Kevin Spacey in 21 Courtesy of Columbia Pictures

READ MORE: 21 review

Following an astonishing run in the '90s that encompassed Se7en, L.A. Confidential, Glengarry Glen Ross and The Usual Suspects — and culminated with his Best Actor Oscar for American Beauty at the turn of the millennium — Kevin Spacey was commonly hailed as the best actor of his generation. Then the theatre scene diverted his focus and he immigrated to the UK to take the reins at London's prestigious Old Vic theatre, which he's been running for the past five years (he's currently appearing there alongside Jeff Goldblum in a production of David Mamet's Speed-the-Plow).

But Spacey still adores movies and his production company Trigger Street is releasing their biggest project yet, 21, about a gang of geeky M.I.T. math geniuses who learn how to card-count while playing blackjack so they can fleece Las Vegas casinos for millions. Based on a true story, Spacey plays a (fictional) professor who mentors and bankrolls 21's gambling brainiacs.

Ensconced in London's chic Soho Hotel, Spacey is sitting on an overstuffed sofa with his black wire-haired terrier, Minnie, who jumps up to greet us before Spacey shakes our hand. As Minnie lays back down beside her owner, the 48-year-old actor says, "You're such a good interview dog," and prepares to talk 21, winning the Oscar and why he's happier now than at any other point in his career.

Your company Trigger Street developed 21 and you're a producer on the film. What was the appeal for you?
I just always thought that this was a ripe story for a film. As long as 15 years ago, I started to hear rumors from friends in Boston, that there were maybe these kids from MIT who went to Vegas and were making money. But it was like an urban myth — I could never figure out whether it was real or not and no one would go on the record. Then about five years ago, my business partner who runs Trigger Street was walking down the street in New York and he saw Wired magazine where the cover article was, "The True Story Of The MIT Kids Who Took Vegas For Millions," which had been written by Ben Mezrich. Subsequently we discovered his book [Bringing Down The House] and we brought Ben to Los Angeles and strong-armed him into giving us the rights. This being our first big studio film as a production company, I wanted to try to do something that would be entertaining and bring the people in. I hope it's a crowd-pleaser.

It certainly amps up the fantasy-fulfilment side of Las Vegas...
Everybody has that fantasy of going to Vegas and winning a pot of gold. It's also the classic underdog story. It always reminded me a bit of Risky Business. It's about a young person who suddenly finds a way to make a lot of money in an unconventional way and then corruption and greed and all the stuff that comes with that is thrown at him. It's about how a young person eventually decides what kind of a person he wants to be.