Tyler Perry in "Alex Cross."

LOS ANGELES -- It's a rule of thumb that everybody wants to be doing something else. Birds want to swim, fish want to fly.

But Tyler Perry has his own version. He simply wants to do everything.

He's already a playwright, movie director and actor, famous guy-in-a-dress, programming partner on Oprah's OWN network and the face of family-values entertainment for a predominantly African-American TV and film audience.

Now Perry wants to be an action star, in a dark and edgy vein.

"I may lose the grandmothers who come out after church," admits Perry, who's taking on the title role in Alex Cross, a police detective of literary fame previously played by Morgan Freeman in the movies Kiss the Girls (1997) and Along Came A Spider (2001).

"But I'll do something for them later," he goes on. "It's all about evolving, growing and trying something different."

And different it is. For the most part, Perry's career has been spent outside the Hollywood machine, creating plays and movies about a large, sassy, gun-toting grandma named Madea. Or he's made moral fables such as Good Deeds or Why Did I Get Married?, in which well-meaning but confused protagonists discover (often at church) what really matters in life.

What you won't find is serial killers and ritual torture.

"I really committed to being this character," he says of Cross, who spends the movie in a battle of wits with a psychotic killer called Picasso (a lean and insanely muscular Matthew Fox), so named for the sketches he leaves behind at his high-profile killings.

"I spent a lot of time with the Atlanta police department (Perry lives there, and has shot films there as well), with their homicide squad, looking at cold cases and being involved in things I don't do in my everyday life.

"And after it was all over, I had to check in with myself to see how I feel about it. Because when you take on something that dark you really have to commit and go to some dark places."

Box office willing, Alex Cross (in theatres Friday) is designed to be a franchise. But Perry says, "I'd have to see how far I'd have to take my body, soul and spirit into that kind of world before I'd agree to do it again."

A burly 6-foot-2 and 260 pounds, people in Hollywood have looked at Perry before and thought what he might look like, guns-a-blazing.

Alex Cross director Rob Cohen (The Fast and the Furious, xXx) remembers thinking as much on first meeting him.

"Tyler Perry's agent at William Morris invited me to go see the theatre version of Madea's Family Reunion. And I had not to that point seen a Tyler Perry film. But I was very curious because I'd been watching what those films did at the box office.

"I went backstage afterwards, and when he walked in the room I was stunned.

"He is a very big man. The first thing I said was, 'Y'know, you could be an action star.' And he said, 'Well, find me something. We'll do xXx or something.' "

A year later, Cohen was approached to direct Alex Cross, an origin story set in Detroit, and not based on any of the James Patterson novels -- though the author does own 40% of the film. For the record, he says Perry is physically closer to the way he envisioned Cross than Morgan Freeman

"They said, 'We've had conversations with Tyler Perry,' " Cohen recalls. And I said, 'Now I'm really interested.' "

Still, a jump to the action world comes with physical demands.

Fox did the most impressive job sculpting his body. As for motivating Perry, Cohen said all he had to do was apprise him of the fact that he'd be doing a scene in bed with his wife with his shirt off. "That was enough to motivate him," Cohen says with a laugh.

Perry's weight-loss regimen involved intensive training in Krav Maga, the Israeli martial arts discipline.

"It was Rob's idea that I start taking it, and I fell in love with it," Perry says.

"It is the most intense experience I've ever had in my life, and I kept it up after the movie because it's so relaxing and being able to defend yourself, that's really cool. It helps me keep my weight down, so it's really intense.

"I can kick the matt, man. Thanks Israel!"

As for the future, Perry says Madea fans need not fret. (Madea's Witness Protection Program came out this year).

"That old broad's going to die a slow death," he quips.

And then there's Perry's deal with OWN.

He has created African-American TV series before, including Meet the Browns and House of Payne. But industry observers say this deal puts him firmly in the category of entertainment mogul.

"I didn't put that on me," he says of the word mogul. "I'm just trying to be true to everything that's in my brain, whether I want to do television, I want to do movies. We all should be able to do what we want to do, how we want do it.

"Oprah and I have been talking from the beginning. I thought it was a great opportunity for both of us to partner up. And it's a win-win because I get an opportunity to give her what she needs, which is programming. And I get to learn how to run a network.

"Norman Lear is my all-time ultimate hero," he says of the '70s TV legend who created shows from All In the Family to Maude to The Jeffersons.

"That's one person I'm looking forward to meeting."

Other popular literary characters played by various actors:

The name may be familiar, but you can always replace the face. Tyler Perry is stepping into the role of police psychologist Alex Cross -- a character played twice earlier by Morgan Freeman. And Detective Cross joins a pantheon of literary characters who've been played by different actors over the years. Here's a sampling:

Arthur Conan Doyle's Sherlock Holmes: ("The most portrayed movie character" according to Guinness, 254 times in film and TV): Includes Basil Rathbone, Peter Cushing, Fritz Weaver, Nicol Williamson, Christopher Plummer, Christopher Lee and Robert Downey Jr.

Ian Fleming's James Bond: Sean Connery, George Lazenby, Roger Moore, Timothy Dalton, Pierce Brosnan, Daniel Craig.

Tom Clancy's Jack Ryan: Alec Baldwin, Harrison Ford, Ben Affleck, Christopher Pine (in the upcoming prequel Jack Ryan).

Raymond Chandler's Phillip Marlowe: Dick Powell, Humphrey Bogart, Robert Montgomery, George Montgomery, James Garner, Elliott Gould, Robert Mitchum.

Dashiell Hammett's Sam Spade: Ricardo Cortez, Humphrey Bogart, George Segal (as Sam Spade Jr. in The Black Bird).

Shakespeare's Hamlet: Laurence Olivier, Nicol Williamson, Mel Gibson.

Bram Stoker's Dracula: Hundreds, including Bela Lugosi, John Carradine, Christopher Lee, Frank Langella, Gary Oldman, George Hamilton and Leslie Nielsen.

Lewis Carroll's Alice In Wonderland: Ruth Gilbert, Charlotte Henry, Kathryn Beaumont (voice, in the Disney classic), Fiona Fullerton, Mia Wasikowska.

J.M. Barrie's Peter Pan: Bobby Driscoll (voice, in the Disney classic), Robin Williams, Jeremy Sumter, Rick Sparks. Barrie himself was played by Johnny Depp in Finding Neverland.