Joe Jonas Celebrates 21st Birthday Onstage

'I hope you can fit a car on there,' Joe jokes as brothers Kevin and Nick surprise him with cake at Hershey, Pennsylvania, show.

Joe Jonas celebrated a major milestone on Sunday when he turned 21. But his brothers decided to start the celebration a few hours early on Saturday night while onstage during a Hershey, Pennsylvania, show. Kevin and Nick wouldn’t let Joe get through the Hershey Stadium concert without acknowledging his big day in front of their fans.

In online footage, Kevin tells Joe, “I think it’s important that we celebrate with our friends as well. So we wanna bring out a little something for you, Joe.”

Just before a cake was brought out to him, Joe joked, “I hope you can fit a car on there.” “In the meantime,” Nick said to the fans, “why don’t we sing happy birthday to Joe?”

As the crowd sang out to Joe, Kevin’s wife, Danielle, and a female friend carried out the birthday cake but had some problems lighting the candles. With a little assistance from the birthday boy, one candle was lit, and then Joe took a second to think about what he wanted to wish for.

“That’s really good cake,” Joe told fans as he took a bite. “Thank you, guys!”

So, did Joe enjoy the big surprise? It seems so. He later tweeted, “:)… Ohhh boyyy… That show was amazing!”

Although there’s no word yet how he celebrated his birthday proper, when the Jonas Brothers stopped by “Good Morning America” last Friday, Joe teased that some plans were in the works. “Besides a dog, I don’t know. That’s all I kind of wanted. I don’t know [what we're going to do to celebrate]. These guys are not telling me what they’re doing.”

In the days before his big 21st, Joe tweeted about his one birthday gift demand: “I had a dream last night I got a dog for my birthday. The dog had huge puppet eyes. When I picked it up he said ‘oh hey Joe.’ ”

Nick also tweeted some birthday wishes, via their dad’s Twitter page. “RT @PapaJonas Big Day! Joe’s 21st Birthday, my 25th Anniversary AND JONAS LA tonight on Disney,” he wrote.

Tourmate and “Camp Rock 2″ castmate (not to mention ex-girlfriend) Demi Lovato was a bit late to the party, but made time to tweet Joe a birthday wish on Monday (August 16), writing, “Ah happy late bday @joejonas!”

Share your birthday wishes with Joe in the comments below!