Even though Billy Joel is 69 years old and has been performing for ages, the man still sells out every single show. People love, *searches for his nicknames*, the Piano Man. They love Mr. Long Island. But while Billy has millions of fans, his biggest fan might just be his three-year-old daughter, Della. And wouldn’t you know it, but his biggest fan just got to perform with him at Madison Square Garden.

It wasn’t just Billy on-stage at MSG on Tuesday, Dec. 18, as Billy first found himself performing with his 32-year-old daughter, Alexa Ray, which we’re sure the crowd was all about. But then Billy was joined by an unexpected guest when Della grabbed the microphone and sang with her dad, all while wearing a set of Christmas pajamas. And these weren’t just any pajamas. These had Mrs. Claus on it. And that’s pretty legit where we come from. Della even had a pair of Adidas sneakers on. It was pretty clear that Della was cooler than anyone there.

And sure, Billy is up there in age but he’s still bringing in kids, as he and his wife Alexis Roderick welcomed Della in 2015 and her little sister, Remy, in 2017. And now three years later, Della is doing things that most of us can only dream of doing.

See how Della did by taking a look at these fantastic photos — scroll down!