We take it this means he's forgiven her.
Well, it appears that it only takes two months to heal a broken heart in Hollywood, because reports are suggesting that not only has Bobby P taken Kristen back - but he also wants her to marry him.
"Rob told Kristen the only way he can forgive her affair is if she truly commits to him," a source told the Daily Star. "Rob has been keen to marry Kristen for quite a while and he doesn't want to get back with her unless he knows she means it for life too."
"Although Kristen broke Rob's heart he has realised he can't live without her. He never stopped loving her and he believes she still loves him.
"He is desperate to make it work and wants to give her another chance but not unless she proves she really wants it too.
"They have both talked openly about marriage before and she's been telling him for years that she doesn't want to rush into anything. But Kristen will do anything to get back with Rob now and one of the conditions is to discuss getting married and the future."
Conditions? Is it just us, or does this sound strangely familiar? Oh, yeah - it's exactly the same as the plot of Twilight Eclipse - when Edward won't turn Bella into a blood-sucking vampire until she agrees to marry him.
We wonder if that's where Rob got his 'ultimatum' idea.
What do you think about the latest Robsten rumours?