IT LOOKS like going on tour with Elton John has broken up Billy Joel's marriage.

Or maybe it was the 30-year age difference.

Whatever. "Extra" reports that the Piano Man and wife No. 3, Katie Lee Joel, have separated.

It's confirmed in a statement from both of their reps (why does she have a rep?):

"After nearly five years of marriage Billy Joel & Katie Lee Joel have decided to separate. This decision is a result of much thoughtful consideration. Billy & Katie remain caring friends with admiration and respect for each other."

We'll see how caring and respectful they are when the papers are filed.

'Grey's': Good Knight, T.R.

Sorry, "Anatomy" fans, Dr. O'Malley couldn't be saved at Seattle Grace.

Entertainment Weekly's Ausiello Files (at EW.com) are reporting that T.R. Knight is done with "Grey's Anatomy."

ABC is letting him out of his contract so he can possibly star in a Broadway revival of "Lend Me a Tenor," in 2010.

In other "Grey's" news, Jessica Capshaw (Callie's lady love Arizona) will become a series regular.

So it wasn't Callie's lesbian relationship with Dr. Hahn (the suddenly fired Brooke Smith) that was a problem for ABC.

The alphabet network just wanted a younger, prettier lesbian.

Off to see the Wizard World

The comics/sci-fi/gaming universe of Wizard World takes over the Convention Center (12th and Arch streets) this weekend, and the wildest after-party will probably be hosted by Fort Washington-based Zenescope, 8 p.m. Saturday at Zee Bar (100 Spring Garden St.).

The party is for Zenescope's "Grimm Fairy Tales," and will feature a fairy-tale-costume contest for Zenescope's ongoing "Girl of the Month."

Who knew Little Red Riding Hood was such a minx?

The grand prize for the contest winner includes $250, a free photo shoot by renowned pin-up photog Celeste Giuliano and a chance to win a trip to Comic Con 2010 in San Diego.

Tickets are $10 at the door or $5 if purchased in advance online at www.zenescope.com. Women in costume get in free. You must be 21 or older to enter.

* Returning to Wizard World

Philadelphia for the first time in a few years is model/actress Chanel Ryan, originally from Allentown.

Chanel will be at the convention all three days signing autographs and greeting fans of her swimsuit calendars. For more information on Chanel, check out www. chanelryan.

com.

Tattbits

* Actress

Shohreh Aghdashloo

will attend a screening of "The Stoning of Soraya M.," at 7 tonight at the Bridge (40th & Walnut). The event is presented by Women's Campaign International, whose founder, former U.S. Rep. Marjorie Margolies-Mezvinsky, will moderate a panel discussion following the screening. Aghdashloo; Richard Gelles, dean of Penn's School of Social Work, and Penn professor Susan Sorenson will also speak after the film, which is based on the international best-selling book by French-Iranian journalist Freidoune Sahebjam. The screening is free but you must RSVP to attend, at 215-387-2603. Few seats remain.

* "Gossip Girl's" Chace Craw-

ford, 23, is People magazine's hottest bachelor of the summer.

Hottest? Given the weather so far, shouldn't he be the wettest?

Also on People's list: Philadelphia's own Bradley Cooper.

* Twitter may be working wonders in disseminating info on the people's protests in Iran, but it has ticked off Lindsay Lohan.

Lindsay spoke with Life & Style about allegations that she Twittered that she saw Justin Timberlake cheat on Jessica Biel this week.

Lindsay denies it.

"I would not discuss my personal life, let alone someone else's, on the Internet!" she told Life & Style.

Lindsay, are you saying your Twitter account was hacked?

"Clearly! Twitter needs to fix their s---. . . . It's annoying."

* The Hollywood Reporter says

Sean Penn has dropped out of two films: The crime thriller "Cartel" and the nyuk-nyuk comedy "The Three Stooges."

Oh, no! Who will play Larry?

* According to casting elves at

the Hollywood Reporter, Greg Kinnear and Kelly Preston will play Miley Cyrus' parents in "The Last Song," to be adapted from a Nicholas Sparks novel.

It's about a rebellious teenager (Cyrus) forced to spend the summer with her estranged father.

Sounds like "Georgia Rule" with Miley playing Lindsay Lohan and Kinnear as Jane Fonda.

* The remake craze continues

with word of a new take on 1935's "The Bride of Frankenstein."

The Hollywood Reporter says Neil Burger ("The Illusionist") may write and direct.

"Bride" was remade in 1985 with Sting and Jennifer Beals.

How'd that work out?

* How do you get to Carnegie Hall?

Forget practice. Be funny.

Ricky Gervais, Tracy Morgan and Bill Maher will headline the sixth annual New York Comedy Festival in November.

Organizers announced yesterday that Gervais and Morgan will perform at Carnegie Hall and that Maher will play Avery Fisher Hall at Lincoln Center.

Gervais noted that Carnegie Hall was near his apartment.

"I can walk to work," he said. "I won't walk, obviously. I'll take a limo. But I could walk if I had to."

* Writer/director Judd Apatow

in the new Playboy on why penises are so funny (and so often in his films): "A penis looks like a man with a big nose and large ears." *

Daily News wire services contributed to this report.

Send e-mail to gensleh@phillynews.com.