Superstar Kat will marry superstar Bastian on stage in a very official wedding in front of an audience. Just before she goes on stage, she gets to see a YouTube clip where Bastian is cheating on her own assistant. Devastated, she steps onto the stage and interrupts the whole thing with a speech, and during the speech she sees the single father Charlie, who has been dragged to the concert by a colleague. He happens to be temporarily holding a sign that someone stuck to him that says "Marry Me" and in a momentary inspiration, Kat invites him up on stage and does just that. Now they both have to deal with this impulse and Charlie is thrown into a merry-go-round he was not at all prepared for.
The movie could have been better. It's good, but Owen Wilson pulls the whole thing down as usual. The film would have been much better with any other actor.