Cyrus previously told Digital Spy that the movie, a remake of a 2008 French comedy, is about the bond between her character Lola and Moore's Anne.
"It's about this mum who's going through a mid-life crisis of drugs and all this crazy stuff and she thinks that her daughter will never understand and look up to her anymore because of the choices she makes," she said.
"She then finds her daughter's diary and realises that she's doing worse than her and they go through this crisis together at different points of their life but realise how similar they are. I think it's a really cool story.
"We're shooting it independently so we can do it with exactly the edginess we want."
Twilight's Ashley Greene, Douglas Booth and Thomas Jane co-star in LOL, opening May 4 in the US and June 1 in the UK.
> Watch Miley Cyrus in the trailer for LOL
LOL pictures - view photos from Miley Cyrus and Demi Moore's latest movie: