Even though her birthday was yesterday, today's Ellen DeGeneres Show featured one last celebration: a surprise call-in song from Lady Gaga! After the serenade, Gaga and DeGeneres discussed the singer's new album, upcoming Grammy performance, and frustration with NYC weather.

Ellen Degeneres turned 53—that's right 53—today and her show was filled with birthday fun. There was a performance from the "Double Dream Hands" guy and Colin open-mouth kissed Ellen while Portia de Rossi watched.

Joel began his interview on Ellen's couch today by bringing up the sting of rejection he felt when he didn't get the part on Ellen's sitcom years ago. He doesn't hold a grudge, though, because his wife loves Ellen's show.

When Amy Poehler heard the news that her nanny walked right through the cameras while Kyle Richards was working out in the park, she had just one question about the Housewives—"Is it Desperate or is it Real?"

Have you overdosed on Natalie Portman coverage yet? Here are two clips from today's Ellen. In the first, Natalie helps Ellen channel her inner "Black Swan," and in the second Ellen tries to determine the sex of the baby.

The newest pint-sized member of Jersey Shore took to Ellen's couch today to talk about her experiences on the show. Ellen grills her about getting naked on the first episode and which of her roommates she has a crush on.

We figure there's an average of two comments about how much of a bad host Ellen Degeneres is every time Gawker.TV posts a clip from Ellen. Haters, it appears that Family Guy agrees with you.

The Real Housewives' Kyle Richards visited the Ellen set today and conversation immediately turned to crazy ol' Camille. As it turns out, Kyle and Camille aren't as friendly as previously advertised.

Last year, Ricky got lucky with celebrity-scandal-material, saying "Mel Gibson was a gift from the comedy God" This year, he thinks he'll concentrate on Charlie Sheen. He won't go after someone like Russel Crowe, though, for fear they'll attack him.

Here's a peek behind the scenes of Ellen during a commercial break. Apparently, Richard Simmons thinks his side job is as Ellen's warm-up dancer.

If you thought the other interviews with celebrities exercising were weird—well, this one takes the cake. Ryan Gosling did his Ellen interview while exercising, wearing onesie pajamas, and dodging questions about a romance with co-star Michelle Williams.

Everyone loves a good mustache joke, and in honor of her first guest of the day, Ellen gave her audience stick-on mustaches. The weird thing was, Tom Selleck never acknowledged this fact. Did he even notice?

Nicole Polizzi (née Snooki) was on The Ellen DeGeneres Show today. After DeGeneres reminded Snooki that she dressed up as the Jersey Shore star's poof for Halloween, the costume made a surprise appearance... and Snooki screamed. Loudly. Watch inside.

For reasons unknown (other than "I heard there was going to be break dancing" and "I got a lot of Christmas presents") Jimmy Kimmel wore a suit made of bubble wrap to Ellen's set today. See what (predictably) unfolds inside.

Yesterday was a good day for Marky Mark, with his numerous Golden Globe nominations (one for Boardwalk Empire, six for The Fighter.) The awards-season talk was going just fine until Mark Wahlberg and Ellen have an weird, impromptu dance session.

With only 7 more episodes left for Michael Scott, Ellen asked Steve Carrell about his replacement: "I think it would be in their interest to go in a different direction and not try to do the same type of character."

Jamie Foxx is full of holiday cheer! Not only does he sing in this clip, he also can't remember the word for "sled." Ellen watches in amazement as he entertains us with his thought process.

On Ellen, Jane Fonda recounted a Fonda vs. Wild-esque tale in which she was forced to confront a bear that had entered her New Mexico ranch. Aerobics is so 1987; is Survival Tips with Jane Fonda the new straight-to-DVD series?

Today on Ellen, Katy Perry admitted that she's in the process of changing her last name to Brand. She also responded to Helen Mirren's publicized crush on Russell saying "she needs to step off my man" and talked about cats.

Modern Family's Ty Burrell shares his daughter's love for licking electrical outlets yesterday afternoon on Ellen. Apparently even Cayenne pepper can't keep this 10-month-old away. Those teen years should be interesting...