Selena Gomez's on/off boyfriend Justin Bieber has started hanging out with her ex.

Amid ongoing reports his romance with the actress/singer is in trouble, it appears Bieber has struck up a friendship with Jonas Brothers star Nick Jonas.

In a tweet to fans on Friday night, the "Baby" singer wrote, "In the studio tonight working on the acoustic album... had some solid ping pong matches but... still #pingpongchampion."

And Jonas later revealed he was on the other end of Bieber's table tennis challenge, adding, "Just played @justinbieber in ping pong. Went to deuce both times, but he's the ping ping champion. #Igotyounexttime."