‘Joey’

A decade ago, Joey Tribbiani was the vaguest of the friends, handsome and sweet and not too sharp.

And now?

He’s the most important fictional character on NBC’s “Joey,” maybe the one sure comedy hit this fall.

That represents a huge leap from the guy Matt LeBlanc first played on “Friends” in 1994.

“He probably was the thinnest character on the show,” recalls Kevin Bright, a former “Friends” producer who is in charge of the spinoff. “He was this womanizer, but that’s all we knew.”

Viewers rarely heard about his background or saw his family.

“Whenever we would see holidays or family events, it was always the Gellers or the Bings,” LeBlanc says.

“(Joey) was really the least-evolved character of the show.”

Now comes some quick evolution.

When the others decided to end “Friends,” NBC talked LeBlanc and Bright into sticking around for the new series, which premieres Thursday at 8 p.m. in the former “Friends” time slot.

In the first episode, Joey moves to California to spark his acting career. There he spends time with his sister Gina, a hair stylist who knows how to strut.

“She’s really the female mirror image of Joey,” says Drea de Matteo, who plays her. “She knows how to use it; she’s sexually aggressive.”

Joey also encounters Gina’s 20-year-old son Michael (Paulo Costanzo), who is different from his mom.

She was a teen mother and a dropout; he’s a grad student and a rocket scientist.

For de Matteo, this is a lateral move from another hit show. She was the flashy Adriana on “The Sopranos,” until the mob hit decided to erase her character this season.

“I guess I’ll be throwing the punches this time,” de Matteo says. “I’m not going to be getting the (stuffing) beat out of me every week.”

For Costanzo, this is a huge leap. He was only 15 when “Friends” started; he even recalls doing a sketch about the show in high school.

Prior to doing the 2000 movie “Road Trip,” his big role was playing an alien on “Animorphs,” in his native Canada.

“I really got into the character,” he says. “I walked around the set, acting like an alien.”

LeBlanc can easily empathize with the characters in the show.

Like Costanzo’s character, he grew up as an only child; his mother and (later) stepfather raised him in Massachusetts.

“I was sort of conditioned to be alone,” he once said.

He tackled New York to study acting. Then, like Joey, he tried the culture shock of California.

“I had to buy a car, and you drive everywhere,” LeBlanc says. “I was constantly getting lost. … I got back into the things I did when I was younger — like I would go up to the mountains. I got back into camping. I got back into riding my motorcycle again.”

The Fox network had him star in a bad show (“Top of the Heap”) and a worse spinoff, “Vinnie and Bobby.” Then “Friends” came along.

At first, the Joey character seemed to offer only the obvious: a happy womanizer who wasn’t very smart. But soon, Bright says, the writers began to give Joey the sweetness and warmth of the actor who plays him.

“With the exception of the stupidity, Matt is a lot like Joey, being a guy with a huge heart,” he says.

Now that character begins his transformation.

In the first episode, he says he didn’t really want to change but had little choice.

“I agree with that speech,” LeBlanc says. “Change can be good. It’s hard, it’s a little scary, but … go out there and take a shot.”

Forced to be on his own, the character will probably seem a tad wiser.

“It’s kind of a more evolved Joey,” LeBlanc says.

Still, it’s not a huge change.

“A lot of times, when you take a character from one show and spin it off to another show, it seems like people change that character too much,” LeBlanc says.

That won’t happen this time, Bright promises.

“We’re not going to reinvent Joey.”

The character will remain sort of sweet and dim and boyish, trying to be on his own after a decade with some great friends.