When Lorde brought her "Homemade Dynamite" to Montreal's Osheaga Music and Arts Festival, she invited a very "Cool Girl" to join her onstage: Tove Lo, who co-wrote the song, Melodrama's hypnotic third track.

"I wrote all the songs on Melodrama with one person, and she was the one extra [person] who I wrote a song with," Lorde revealed during her set last weekend, also referencing Jack Antonoff's production and writing help. "I had such a great time with her, so when she comes out onto the stage, Osheaga, I need you to give her your very biggest welcome, is that understood? Good."

Tove Lo echoed this excitement on Instagram, where she wrote about what a "huge moment" this was for her. She'd already played her own Osheaga set, but now she was part of Friday's big headlining performance too.

The Lady Wood singer whipped out the same dreamy, uninhibited dance moves we've come to expect from Lorde, creating an explosive experience for the thousands of fans cheering them on. Watch it all go down in the fan-shot video below.