As Louie De Palma on the TV comedy "Taxi," Danny DeVito embodied the guy audiences loved to hate — a crude, obnoxious boss who would torment his employees at the Sunshine Cab Co. with sadistic glee.

Some 23 years since "Taxi's" curtain call, DeVito, 61, returns this week as a TV-series regular, playing another loathsome yet lovable role on tonight's second-season premiere of the FX comedy "It's Always Sunny in Philadelphia."

Just how bad is his character on the show, Frank Reynolds, compared to Louie? Don't ask DeVito.

"I don't think Louie was a creep. And I think Frank is a really honorable man," the actor deadpans before busting into a laugh that says 'gotcha.'

Apart from a memorable cameo on "Friends" doing a striptease, or appearances on "Saturday Night Live," since "Taxi" DeVito has stayed away from regular TV series work and concentrated on movies — acting, directing and producing.

His screen credits include roles in "Romancing the Stone," "Twins" and "Batman Returns." He also executive-produced "Pulp Fiction" and directed "Hoffa" and "War of the Roses," among others.

But all the while, DeVito says, he's been craving a return to a sitcom.

"I was always looking for something that was exciting, something to give me the juice to be with actors on a stage," he says, relaxing at a post-screening party Sunday.

"Sunny" centers on four self-involved friends pushing 30 — Mac, Dennis, Charlie and Sweet Dee — who run a dive in Philadelphia and often fall victim to each others' chronic misguidedness.

"These guys always manage to find the lowest common denominator in any choice that they make in terms of their lives in the bar or trying to get over on people," DeVito says in a heavy New Jersey accent.

DeVito enters the fray as Dennis and Sweet Dee's estranged father, Frank, who barges into the foursome's lives after announcing that he and his wife (Anne Archer) are getting divorced.

Frank wants to bond with the kids he all but ignored for 30 years. He wants to give away all his money to charity and live a simpler life. But most of all, it seems from the first few episodes, Frank really wants to just hook up with young, hot women — often at the expense of the younger guys.

"The Danny character was an expansion of these characters' world. You get to see a little bit of where these people came from and, unfortunately, a sense of where they're going to end up," says Rob McElhenney, who plays Mac and, along with co-stars Charlie Day (Charlie) and Glenn Howerton (Dennis), also works as executive producer and writer on the show.

Kaitlin Olson, 30, rounds out the cast of regulars as Sweet Dee.

Having DeVito on the show has been the latest stroke of fortune for McElhenney, 29, and Howerton and Day, both 30, who landed the series on the strength of a pilot they shot for less than $200, or so the story goes.

"We have come a long way from a home movie that was shot with a couple of friends," McElhenney reflected at recent screening of the episodes from the upcoming season.

DeVito came across "Sunny" last year when John Landgraf, FX president and general manager, and a longtime associate of DeVito, sent the actor copies of the show.

DeVito loved it, and soon McElhenney was at his door, asking him if he would consider joining the cast.

"I said I would do it like if the character was organic and didn't feel tacked on," DeVito says. "Once I heard what they wanted to do, and that they were going to write this character of Frank Reynolds and how it was going to fit into the mix, I was sold."