Complex sentence: Like Prince Charming, it has not been confirmed that Mabel will return for the fourth film, set to be released theatrically in 2010; however, since Doris is returning, it is possible for Mabel to return too.
Split into simpler sentences: Like Prince Charming, it has not been confirmed that Mabel will return for the fourth film, set to be released theatrically in 2010. However, since Doris is returning, it is possible for Mabel to return too.