Usually as innocent as ever, Sel surprised us when she admitted to Jay that she was actually a bit hung over at the time. She even told him that she took shots of Jack Daniels when she partied and celebrated her b-day with friends!
"Are you hungover today, was it a big party?" Jay asked.
"A little bit, it was fun though, it was good," Selena replied.
Selena isn't done partying either. She totally talked about her upcoming birthday party this Saturday too.
"I'll have a birthday party this weekend but I had a dinner with my friends, the party's going to be kind of a gypsy theme, I'm excited," she said.
"We're gonna have skirts and tattoos and belly dancers. It'll be kind of the whole thing, It'll be fun."
We can only imagine who is going to show up for that party! Hmm, Justin Bieber and/or Taylor Swift, maybe?
Watch Selena on The Tonight Show above!
Click to see Selena's birthday cake from her friends!