Demi Lovato celebrated her birthday with fellow pop star Ariana Grande this year.

The "Sorry Not Sorry singer rang in her 27th year by attending Grande's concert on Monday (August 19) with manager Scooter Braun. In a series of videos uploaded to her Instagram Story, Lovato is seen having the time of her life as she attended the "Boyfriend" hitmaker's Sweetener World Tour stop at London's O2 Arena.

She and Braun also spent time with Grande backstage where her crew huddled for a pre-concert prayer and did a little birthday chant. Lovato posted the moment on Instagram, which also sees her and Grande share a sweet hug.

"This was too sweet not to post.... before show prayer they did this for my bday. I’m so so proud of you @arianagrande. You fucking killed that!!! I love you tons," she captioned the video.

But the celebrations didn't end there. After the concert, Lovato shared another video of Grande, Braun and the crew singing her happy birthday as she blows out candles on a cake.

"Okay, last one before bed. They literally filmed/sang happy birthday twice and @scooterbraun STILL forgot to press record @arianagrande’s face is everything and this video is a perfect glimpse of how f---ing happy and rad my birthday is this year. So so happy. And I love my new family. Thank you guys, love you."

As previously reported, Lovato hired Braun as her manager earlier this year and joined his professional family which includes Grande, Justin Bieber and more.

12 Female Celebrity Friendships That Have Outlasted the Spotlight

More From 107.3 KFFM