It looks like the Knocked Up spin-off This Is Forty will get getting another cast member from the original.  Megan Fox posted a picture of her on the set in a swimming pool with co-stars Chris O'Dowd (Bridesmaids) and Jason Segel.  As you'll recall, Segel played one of the friends of Seth Rogen's character in Knocked Up. He'll be joining stars Paul Rudd and Leslie Mann who are reprising their roles as married couple Pete and Debbie in the Judd Apatow comedy, which Rudd recently said is a "companion piece" to Knocked Up and not a sequel.Segel will also be starring alongside returning cast member Charlene Yi as well as Albert Brooks, Megan Fox, Chris O’Dowd, Lena Dunham, Melissa McCarthy, Ryan Lee, and Wyatt Russell.  This Is Forty is set to open in December 2012. [Update: Apparently there have been set photos of Segel on set with Mann.  I never saw those, hence this story.]