In the caption below the photos of Billie with the girls she filmed the video with, Billie wrote "I love girls." Most fans of the singer had presumed that she was straight, but thanks to this provocative comment, some are now wondering if she wrote the caption as a way to come out.

"If you say you straight after this ISTG," one user wrote in the comments. The post features a number of similar comments, all wondering if Billie chose this moment, during PRIDE, to come out.

Ultimately, though, it's unclear whether Billie intended her comment to be interpreted that way. In spite of her enormous fame, the singer has always been tight-lipped about her love life.

In The World's a Little Blurry, the documentary focused on Billie's life as she rose to fame, many fans discovered that she was dating her now-ex-boyfriend Brandon Quentin Adams.

"Lost Cause" is clearly a song describing Brandon, who she seems to largely describe as a bum. Although the song may be about her past relationship, the video had a somewhat perplexing effect on Billie's fans, in part because she's surrounded by women and is moving in a sensual manner.

Although there's been plenty of speculation about Billie's sexuality, there's also been some discussion around the possibility that "Lost Cause" is an example of queerbaiting.

Queerbaiting is used to describe the practice of acting sexual with members of your own gender in order to draw a bigger audience. 

It may seem unlikely that Billie would do something so carefully calculated, but fans haven't dismissed the idea entirely.