We didn't see that one coming.
Well actually, considering how much time they have spent together since breaking up, we sort of did.
The pop pair were spotted leaving Selena Gomez's Californian pad yesterday in Justin's rather swanky white Ferrari.
[Related article: Selena Gomez puts relationship troubles aside, poses with male model]
[Related article: Selena Gomez calls Justin Bieber a jerk]
Perhaps she was simply impressed by the fact that the 18-year-old DRIVES a Ferrari.
At that age we had a 1998 second hand Corsa.
The two then headed off to Justin Bieber's house following their night together.
Selena broke things off with Justin last month after it was revealed that the 'Baby' singer had invited model Barbara Palvin to join him in his dressing room after he performed at a Victoria's Secret show.
Selena has however now put Justin's indiscretion behind her.
But not without making him sweat a little first.
Congratulations to Selena, we don't doubt Justin has rarely begged for anything in his life.
The source said: "After a lot of begging Justin's eventually been forgiven and has had to admit he's messed up.
"It's early days but she's taken him back and told him to clean up his act."
Well as long as he refrains from hanging out with models on his own in the future, we think they'll be fine.