Justin Bieber bought shots for college students while out partying!

College students must've thought it was their lucky day when Justin Bieber turned up at their uni bar to buy them free drinks!

We hear the 21-year-old singer - who recently cancelled a string of planned appearances amid claims he needed a break from his hectic schedule - stopped by the 901 Bar and Grill at the University of Southern California (USC) and bought drinks for a number of people!

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Fans took to social media to share pictures and videos with one person writing, "When @justinbieber buys you shots at the 9-0 #FightOn" and another added, "@justinbieber went to the 9-0 at USC tonight after performing with @TheChainsmokers at The Shrine and I can't even."

Justin stopped by the bar after making a surprise appearance at The Chainsmoker's show that evening.

Meanwhile, the What Do You Mean singer recently cancelled a series of performances - including an appearance on The Late Show With Stephen Colbert - without offering a proper explanation and took to his Twitter account to say sorry to those people who were hoping to see him.

Justin said: "My apologies to @colbertlateshow as I won't be able to make it to nyc for the show. I look forward to making it up to you soon. (sic)"

Later, he thanked his fans for their understanding, though he again declined the chance to explain the problem.

He wrote: "@StephenAtHome thank you for the understanding as sometimes life kicks our ass and we need to deal with it. I will see u soon. Thank you (sic)"

Gossip website TMZ said Justin has been on an emotional roller-coaster in recent weeks and simply could not continue with his hectic schedule.

We hope you take some time off to rest, Biebs!