She might have been missing in "Hangover 2," but Heather Graham will be back for the third installment in the series, Variety is reporting. She wed Ed Helm's character in the first film, but he wed Jamie Chung in the second. Will her appearance in "Hangover 3" cause some marital strife? Who knows. The plot details are still being worked out, but she will join the ensemble cast -- which will include some celebrity cameos -- to round out the series.