At the Toronto International Film Festival, where the movie had its premiere, she indicated that she wasn't just being self-effacing:
"So I actually gained 20 pounds for the role. I wanted to be lumpier. I said, wouldn’t it be interesting to have a posture of a lady caveman. I’m really happy with that."
That does sound kind of fun, actually.
- Aug. 24, 2016 Britney Spears reveals she almost drowned in Hawaii