Robert is known for his role as vampire Edward Cullen in hit franchise Twilight, and fellow Brit James takes on the role of a vampire in the forthcoming third series of True Blood.
But James said he and Robert did not talk about vampires while on the set of their film, which also stars Reese Witherspoon.
He said: "My scenes were with Robert Pattinson but I'm sorry to say we didn't swap vampire stories. I wish we had.
"People can't believe there's going to be a scene in the movie with a Twilight vampire talking to a True Blood vampire and that we didn't spend our time chatting about that, but I'm afraid not. I wish I'd got vampire tips from him, I wish I'd gone 'Oi, Bob mate, any tips?'."
But James was full of praise for Robert, saying: "He's sweet, quite shy, just a really good guy."
Water For Elephants, which is based on a book about a travelling circus, is due out in April 2011.
Frain plays Rosie's caretaker as per his IMDb page