Billie Eilish surprises brother Finneas during Los Angeles show

Billie Eilish left her brother Finneas surprised when she came on stage during The Troubadour Thursday night in Los Angeles to perform.

In multiple videos on TikTok taken by a fan, the singer could be seen performing Happier Than Ever with her brother. 

This came to as a surprise to fans as even they were left in the dark about her coming on stage to perform.