Disney Channel fans are gonna flip for this Camp Rock reunion.
During Demi Lovato's concert at Los Angeles' Staples Center on Saturday night, Joe Jonas showed up to perform their Camp Rock hit "This Is Me," nearly six years after the TV movie premiered.
NEWS: Demi Lovato Is Ready to Have Babies!
"Surprise LA! @DDLovato thank you for having me," the former Jonas Brothers member, 25, tweeted. "Tonight was amazing. Fun keeping this a secret."
Lovato, 22, Instagrammed a photo from the performance, writing: "Thanks @joejonas for the awesome surprise!! #staplescenter #4yrssincewesangtogether #demiworldtour."
These two weren't just co-stars -- Lovato and Jonas also briefly dated. "I can fortunately say that him, and his brother Nick, have always been there for me and are literally family, and like brothers," Lovato told ABC's Nightline. "We have a great friendship."
PHOTOS: Favorite Cast Reunions
This was a big weekend for Lovato. Her self-titled album Demi went gold while her track "Really Don't Care" went platinum. "Thank you Lovatics + @RIAA!!!" she tweeted to her fans.