Alyson Hannigan has signed to rejoin the cast of the fourth 'American Pie' film.

The 37-year-old actress - who plays band geek Michelle Flaherty in the popular teen comedy franchise - will reprise the role for 'American Reunion' according to

There was considerable concern over whether she would return, as the plot of the new movie is said to revolve around Michelle raising a family with her husband Jim, played by Jason Biggs.

Seann William Scott and Eugene Levy are already on board the movie, which studio bosses at Universal hope will be a big hit in cinemas, unlike past spinoffs which have gone straight to DVD, such as 'American Pie Presents Band Camp'.

Alyson, who is also known for playing Willow in TV series 'Buffy The Vampire Slayer' will work on the film - which starts shooting next month - before returning to her current role on CBS sitcom 'How I Met Your Mother'.