Harry Styles attended Ariana Grande's first UK show of her Sweetener World Tour at the O2 Arena in London on Saturday (August 17). Styles brought his dance moves with him to the show.

Styles stood on the raised soundboard for the entirety of the show. He waved to fans and shook some of their hands during intermissions. Fans didn't know who to watch during the concert since Styles was breaking out in dance.

Styles wasn't the only celebrity in attendance, Stranger Things actress Millie Bobby Brown was also spotted and even spoke with Styles. The pair seemed to hit it off, joking with one another and dancing side by side.

Styles and Grande have been friends over the years, he wrote Grande's song "Just a Little Bit of Your Heart" in 2014. While on tour in 2018, Styles covered the song to honor the victims of the Manchester terrorist attack which took place at the Manchester Arena, where he was performing that night.

Styles' London appearance comes after his recent Scotland trip where he was seen shooting a music video for his forthcoming second album.

Watch the videos of Styles getting his groove on, below!