Did Kristen Stewart Ruin Robert Pattinson's On-Screen Chemistry with Reese Witherspoon?

Actors Robert Pattinson and Reese Witherspoon attend the "Water For Elephants" premiere at the Ziegfeld Theatre on April 17, 2011 in New York City. (Getty Images)more pics »Kristen Stewart (Bauer Griffin)The reviews are in, and the critics agree that Robert Pattinson and Reese Witherspoon have zero chemistry inWater for Elephants. It's so obvious that these two feel nothing for each other that New York Times critic Stephen Holdencomplained that the "romantic chemistry between Ms. Witherspoon and Mr. Pattinson is nil."

He goes on: "When they finally make love in a scene that is so dimly lighted you can hardly see them, it has all the heat of a kissy-poo game of spin the bottle played by 11-year-olds."

So with all this lack of chemistry, is it possible the actors' personal lives are affecting their work? Not only was Reese Witherspoon in the midst of planning her wedding to Jim Toth while filmingWater for Elephants, but Robert Pattinson is rumored to be with his Twilight co-star Kristen Stewart, and is further rumored to be uncommonly devoted to her.

Rob and Kristen are notoriously cagey about the nature of their relationship. Not even Oprah Winfrey could get a straight answer out of them. But if the rumors are true Rob and Kristen share a deep bond that could affect the still young actor's ability to play a romantic lead for any other woman.

Hopefully with time Rob's emotions will settle down comfortably and he'll be able to feel secure in his relationship and still play the part of a man madly in love with his co-star, but for now he doesn't seem up to the challenge. Even Reese Witherspoon has admitted their love scenes were a "disappointment." We'll hope for better in the future.