Right in front of wife Hillary and daughter Chelsea, Lady Gaga serenaded former President Bill Clinton with her rendition of Bill Romance (insert obvious joke here) at a benefit show.

During Saturday's A Decade of Difference benefit to commemorate the tenth anniversary of the William J. Clinton Foundation, Gaga got caught up in a little Bill romance.

Lady Gaga celebrated Clinton's belated 65th birthday, which he celebrated in August, by slipping into something a little more comfortable, or a nude-colored bodysuit. Shortly after an intro, Gaga broke out into an altered version of her 2009 Bad Romance, calling it Bill Romance for the former President.

How cool is it to be 65 and you get Lady Gaga, come on? Clinton said to the crowd at the Hollywood Bowl. I am the only person in history who got to be president, who then had a post-presidential birthday party attended by both Lady Gaga and the Secretary of State, referring to wife Hillary.

Caught on video, Hillary and Bill Clinton seem to be amused and entertained while Chelsea hides her face, possibly in embarrassment, and then begins to sing along. Later, Gaga walks over to Billary, their new Gaga-inspired celebrity nickname, and gets personal, pointing at Bill and serenading him, a la Marilyn Monroe.

Put your hands up for Bill! Gaga said. I love you and your hot wife!

Then right before a small stumble, Gaga proclaimed to the Clintons, It's a good thing I used to dance in bars, right?

The event, which served a double purpose of the tenth anniversary of the William J. Clinton Foundation and for Clinton's belated 65th birthday, also included performances by Stevie Wonder, Bono and the Edge, and Usher.

However, Lady Gaga stole the show with her serenade to Clinton, inspired by Marilyn Monroe in 1962 to then President John F. Kennedy. Later in an interview, she described her Monroe moment.

I always wanted to have one, and I was hoping that it didn't involve pills and a strand of pearls, Gaga said.

Former President Bill Clinton was just as jilted, saying later in an interview, I thought I was going to have a heart attack from Gaga on my birthday.

View the video below to see Lady Gaga's Bill Clinton serenade of Bill Romance.