Ellen Gray | DeVito's the dad in 'Sunny'

IT'S ALWAYS SUNNY IN PHILADELPHIA. 10 and 10:30 p.m. Thursday, FX.

SOMETIMES, DANNY DeVito feels "a little like a vampire."

"I'm pulling in all that positive energy of 28-year-olds and 30-year-olds," DeVito said of his "It's Always Sunny in Philadelphia" co-stars, who, if they happened to overhear him, might already be at work on a script in which the diminutive actor/director's character finds himself on the business end of a wooden stake.

Stranger things have happened, a lot of them on FX's "It's Always Sunny," which enters its third season Thursday with back-to-back episodes in which a) the gang finds a baby in a Dumpster and attempts to get it a modeling contract; and b) Mac (Rob McElhenney) and Dennis (Glenn Howerton) try out for the Eagles in an homage to "Invincible" that ends up with DeVito's character being strung out on acid.

Yes, that's DeVito in the parking lot with Charlie Day at the Linc, one of a number of scenes filmed on location during the cast's most recent trip to its namesake city, where show creator McElhenney grew up.

No, that's not Donovan McNabb playing Donovan McNabb.

Donovan or no Donovan, DeVito called his first visit to Philadelphia with the show "a glorious experience."

"You can't even begin to say how Philly treated us, it was so great. They just opened up the city for us," recalled the actor/director during an FX cocktail party in Beverly Hills, Calif., this summer.

"Rob and I went down and rang the bell for the Stock Exchange. We did all kinds of stuff. Every restaurant, every place you went to, people would just" show their enthusiasm for the show, he said. "And on the street . . . you know, we ran a horse up Market Street or something in one of the episodes. I mean, anytime you want, we'll come back. It was really a lot of fun. I had a ball in Philly."

The "Taxi" veteran's clearly also having a ball on "It's Always Sunny," which he joined at the beginning of Season 2 as Frank Reynolds, the father of Dennis and Dee (Kaitlin Olson).

"These guys are so talented," DeVito said of McElhenney, Howerton and Day, who co-write the show.

"They built the box. This is a whole other kind of comedy, and for me, it's like really refreshing and great. And I always say that this year, we started to take the lid off the box. So we're . . . getting up to speed," he said.

"We did 15 shows this year and . . . we could've done 20, 25. You just keep going. You get on the set and the scripts are funny, but the experience is funnier. It's off the charts with us," DeVito said.

"It's embarrassing sometimes . . . you can't get a line out. I look at Charlie and I'm an actor, I like to be in the limelight. I'm always turning away from camera - you know, I'm about to blow," he added.

"Here's the thing about it," DeVito said. "They're writing the show, they're producing the show - which is big. They're hiring the directors, they're casting the show,

they're editing the show - and they're acting in the show. They're running the show. It's not like you know, you've got Danny and Judd [Hirsch] and Marilu [Henner] and Tony [Danza] and Christopher Lloyd and then you've got Jim Brooks and Ed Weinberger and Stan Daniels and Dave Davis running the show," the way they did on "Taxi."

"It's an amazing amount of work, but they're doing it," he added, laughing. He's happy to let them do it, telling them:

" 'I'll be in my camper, laying down. I'll be back in a minute, see how you guys are doing.' " *

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