Chassagne, a vocalist and multi-instrumentalist for the Grammy Award-winning group, is said to be expecting her first child with Butler, who she married in 2003.
The news emerged after Chassagne debuted a large baby bump when the rockers took the stage in their native Montreal, Canada, for a charity concert on Saturday (23Feb13).
Chassagne has yet to comment on the rumours, but if proved true, she joins Arcade Fire's pregnant touring violist Marika Shaw in the expectant mother club.
Arcade Fire were never going to make your standard fly-on-the-wall documentary. While they appear to...