Ariana Grande Parties With One Direction's Niall Horan in London --- See the Video!

Splash News
Big Sean who?
Moving on from her breakup with the rapper, Ariana Grande was spotted partying with friends in London -- and one of her pals just happens to be a boy band heartthrob.
The "Problems" singer and One Direction's Niall Horan were spotted leaving Ciruque Du Soir Nightclub. On the same night, Grande posted an Instagram video of Horan having fun with helium. "New friends + old friends + helium balloons," she wrote.

Prior to partying, Horan was seen at Grande's show at the O2 Arena on Monday night. 
While the 21-year-old pop star seems to be moving on from her recent breakup, a recent Instagram post from Big Sean has led some to believe that he's not over his ex.

The 27-year-old entertainer posted a pic of him singing on May 29, writing: "Sometimes I close my eyes n pretend it's just me n u."