Katie Holmes will help a good cause and pay homage to screen legend Judy Garland with a starring turn on Fox's So You Think You Can Dance in celebration of the show's 100th episode, set to air July 23.

"She absolutely adores dancing, as does her daughter," says exec producer Nigel Lythgoe, who adds that Tom Cruise's (far, far) better half has been rehearsing till late evening, with breaks to spend time with her 3-year-old, Suri.

Lythgoe says the show, inspired by Garland's song "Get Happy" from the 1950 musical Summer Stock, will feature Holmes in Garlandic attire. She'll wear "the jacket, the little hat," Lythgoe says. "It's just an iconic look. And Katie Holmes has got the legs. Wow!"

Holmes will dedicate her star turn to the Dizzy Feet Foundation, which supports dance education in America.

Awesome! Neil to host Emmys, maybe

Neil Patrick Harris, who recently starred in sci-fi genius Joss Whedon's Web series, Dr. Horrible's Sing-Along Blog, is on the verge of closing a deal to host the 61st annual Emmy Awards on Sept. 20, Variety reports. The How I Met Your Mother star won kudos for hosting the June 7 Tony Awards.

No comment from CBS, which will broadcast the TV industry lovefest.

A bride for a Jonas brother

Kevin Jonas, 21, got down on his knee on Wednesday - not to deliver a smashing song lyric, but to propose to his gf of two years, Danielle Deleasa, 22. Kevin had taken an overnight flight after a show in Vancouver to Danielle's doorstep in North Jersey.

His heart working overtime, he waited.

Then, "she said yes, yes, yes like 500 times super fast in a row," the eldest Jonas Brother's statement says to People mag.

Danielle, a former hairdresser, says she was anything but a groupie when she met her man: "I didn't know who the Jonas Brothers were."

Kevin's parents couldn't be happier. "Our hearts are filled with joy today," Denise and Kevin Jonas Sr. said in a statement. "It is such a blessing that she will be joining our family."

Will his brothers Joe and Nick rib him for settling down so young? We'll see. For now, they write on their Facebook page, "Congrats big brother." A date has yet to be set.

Yesterday, one could hear millions of girls around the world weeping into their pillows.

Reality TV to save Africa

In a move likely to win them the Nobel Peace Prize, cast members of CBS's bug-eating reality hit Survivor yesterday announced they will endure a three-day "fast for the people of Darfur."

In a statement, the cast says it was inspired by Mia Farrow's recent fast, which has been continued by several celebs, including Sir Richard Branson, Peter Gabriel, Maria Bello, Olympic gold medalist Joey Cheek, and New Jersey Democratic Rep. Donald M. Payne.

"While we are known to the world as Survivors, that concept pales in comparison to the survivors in Darfur who have been systematically . . . terrorized . . . by the Sudanese government," says the cast, which is undergoing the heroics voluntarily and not under the auspices of CBS or the show. Info: fastdarfur.org.

'Ice' ices 'Transformers' sequel

Fox's 3-D animated dazzler Ice Age: Dawn of the Dinosaurs earned $14 mil on its opening day Wednesday, according to industry estimates, beating Transformers: Revenge of the Fallen ($10 mil) - but only for the day.

Prognosticators at the Hollywood Reporter say Ice doesn't stand a chance over the holiday weekend against the 'bots sequel, which has amassed $240 mil in the U.S. alone.

Why Aniston was dissed

Now we know why The Hangover star Bradley Cooper publicly repudiated poor, perpetually single divorcee Jennifer Aniston in response to rumors they are romantically involved: Brad is romancing Renée Zellweger. So claims the New York Daily News, which says B.C. and R.Z. "had amazing chemistry" as they dined this week at a New York eatery. They looked "very into each other" as they "giggled and chatted in a corner booth." Not content to just put the knife in Jen's back, the tabloid gives it a twist with this observation: "Throughout the night Zellweger squealed, 'You are so funny!' " Oh, my . . .

Gwyneth: Smash your BlackBerry!

Hispanophile (Iberophile?) Gwyneth Paltrow, 36, who fell in love with Spain 21 years ago as an exchange student, says in a recent interview excerpted by London's Daily Mail and the Associated Press that "Spain has become a second home. . . . Here in the United States an old building is about 17 [years old], and over there it's from 500 B.C. It's incredible."

Gwyn, who has launched a Spanish-language version of her Web site GOOP.com, speaks perfect Spanish and is teaching her kids, Apple and Moses, to speak it. The actress, who shot the PBS series Spain . . . On the Road Again with chef Mario Batali, says the Spanish "seem to enjoy life a little bit more. They aren't running around as much as in New York. They enjoy time with the family. They don't always have their BlackBerrys on."

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