Robert Pattinson and Kristen Stewart are reportedly eager to have a baby.

The pair have been dating since they met on the set of the blockbuster Twilight franchise. In the later movies, Robert and Kristen's characters get married and start a family. It appears that their experience of playing parents on the big screen has inspired them to start thinking about kids in real life.

"Breaking Dawn 2 changed them and made them realise it's something they're ready for sooner and they thought," a source told the US edition of OK! magazine. "They've known for a long time that they wanted kids, but always thought of it as something they would do down the line but then they shot this movie and they started imagining being parents together. The movie really awoke something in both of them."

Sources close to the pair claim they spent a lot of time getting into character for the scenes. This made them both think about their future together.

Now there is speculation that they have told close friends that they would be happy for 22-year-old Kristen to get pregnant now, with a wedding to follow later this year.

"In rehearsals, they would talk a lot about having a baby and all of their feelings about what sort of parents they'd like to be," the source added. "And then when it came time to shoot, they just went for it and really became her parents, even though the girl playing their daughter, Mackenzie Foy, is only ten years younger than Kristen. Bill [Condon, the director] was one of the first to notice how maternal Kristen is. And it wasn't just Kristen Rob was so protective of Mackenzie. He totally jumped into the daddy role."