She's definitely losing it!

Selena Gomez rocked out into her car to Sia's power ballad "Chandelier" and then challenged Chrissy Teigen to a dance off via Instagram on Monday. Oh the marvels of modern technology!

Clad in workout gear and a varsity jacket, the 22-year-old posted a vid of herself doing an interpretive dance (of sorts) whilst in her car. Along with the clip of her wacky moves, Bieber's piece wrote the caption, "Hey @chrissyteigen wanna dance off?" Huh?!

These days it seems like celebs keep challenging other stars to dares via social media. The ALS Ice Bucket Challenge was all the rage last week and over the weekend Britney Spears challenged Katy Perry to do an impression which resulted in a full-on denim explosion on the VMA red carpet. While it's all a bit much -- we think it's funny that the world's most rich and famous are using Twitter and Instagram to force their other famous friends into looking silly. And we love it when celebs make idiots out of themselves!

But back to yesterday's dance-off dare: we think Chrissy, who is a notorious social media fiend, will probably say yes. And given Selena's wild flailing -- we think John Legend's kooky wife will have this one in the bag.

Selena's next stars starring in the dramatic comedy Rudderless, alongside Billy Crudup, Jamie Chung and Anton Yelchin. The film, which hits theaters on Oct. 17, follows a father (Crudup) in mourning, who comes across demo tapes by his son and decides to form a band as a way to cope with his son's death.