"You're Cordially Invited" marks the first time Reese Witherspoon and Will Ferrell have starred in a movie together. The collaboration felt like a long time coming - for one of them, at least. "Nick Stoller, who wrote the movie, he did 'Neighbors' and 'Forgetting Sarah Marshall.' He called me, and he was like, 'So, I have this movie, and it's starring Will Ferrell-' and I was like, 'I'm in,'" Witherspoon revealed during an interview on "The Tonight Show Starring Jimmy Fallon" on Wednesday. The actress then explained that she'd been waiting well over 20 . . .