Robert Pattinson has taken back Kristen Stewart.

The Twilight Saga actor—who was left devastated after discovering his girlfriend of four years had cheated on him with her Snow White and the Huntsman director Rupert Sanders—has decided to give the actress another chance after realizing he can't live without her.

A source told The Sun on Sunday newspaper: "They pretty much decided they couldn't live without each other.

"Kristen poured her heart out to Robert and told him it was a one-off and a mistake."

After the revelations that Kristen, 22, had cheated on the 26-year-old hunk with married-and-father-of-two Rupert, Robert moved out of their Los Angeles home.

However, he has now accepted Kristen's apology for her "stupid mistake" and the pair want to move on with their relationship.

The source added: "Rob sees it as Kristen made a really stupid mistake. After a lot of long tearful talks, they've worked it out.

"Rob can see how truly sorry Kristen is and has totally forgiven her. They really do love each other."

The pair, who have moved back in together, are due to appear on the red carpet together in November for the final Twilight film Breaking Dawn Part 2.