Steve Carell read 40-year-old virgins' case studies to prepare for hit role and discovered common theme

Steve Carell went to unusual lengths to prepare for playing Andy Stitzer in The 40-Year-Old Virgin, including reading case studies about middle-aged virgins.

The 2005 comedy, which just happens to have turned 21 today, follows Andy, an electronics store employee whose co-workers discover during a poker game that he has never had sex.

David, Jay and Cal — played by Paul Rudd, Romany Malco and Seth Rogen — then decide to help him change that, with predictably chaotic results.

Carell co-wrote the movie with director Judd Apatow after first pitching the poker sequence that became central to the story.

Although, when it came to working out who Andy actually was, the research apparently uncovered something much less dramatic than audiences might expect.

Speaking to Radio Free Entertainment around the film's release, Carell explained that Universal had supplied the team with several case studies documenting middle-aged virginity.

Carell’s research helped shape Andy as an ordinary man, not a stereotype (Universal Pictures/YouTube)

It turns out that the common thread was surprisingly simple.

He said: “And what we found to be the case, more often than not, is that they're just normal people who, for one reason or another, never did it, and just very similar to the character, at some point, just kind of gave up on the whole notion because it was harder, to...

“...(every time I say something, all of these really bad puns start floating into the room)...it was more difficult to keep attempting than to just give up.”

Carell said the research helped reinforce the direction they had already imagined for Andy, rather than sending the character towards a more exaggerated stereotype.

He continued: “And what we found just reinforced what we had originally imagined--that this is just a guy. This isn't some incredibly damaged human being. This is just a guy who, for a number of reasons, kind of missed the boat.”

Carell’s infamous waxing scene was filmed for real with five cameras (Universal Pictures/YouTube)

The actor also made clear that Andy wasn't based on one specific person.

Carell joked: “It wasn't based on any, ‘Oh, I know this virgin guy who lives down the street who rides a bike. I'm going to do a movie on him. I hope he doesn't come, because he'll sue us.’ It wasn't anything like that.”

The film's starting point instead came directly from Carell's idea for the poker game, where Andy desperately tries to keep up with the others' stories before exposing how inexperienced he really is.

Asked whether the script was autobiographical, Carell replied: “I will not answer that question. Ummm...it's not autobiographical at all. I, in fact, have two children.”

The research wasn't the only unusual step taken to make the comedy feel authentic.

Carell also famously had his chest waxed for real, with five cameras used because The 40-Year-Old Virgin's crew knew there would only be one chance to capture his reaction.