Do the actors and actresses in Mamma Mia sing the songs live or are they taped before hand?

Question

in the movie

Answer 1

they record in the studio then mouth the words in the movie similar to a music video.

Answer 2

In the Broadway show or the movie? In the movie they are recorded beforehand and then the actors lip-sing when filming.

Answer 3

In the show they sing live.  There are a few shows where certain sections of a song are pre-recorded (bits of Christine's stuff in Phantom) but this is not the norm.  I read somewhere that for the film version of Mamma Mia they pre-recorded the songs as normal, but then instead of lip syncing on set the actors sang at normal volume along with the track, and it was the on-set singing that they used in the film (they took the recorded vocals out of the track) - which apparently is why the soundtrack and the movie sound different.