Lindsay Lohan and Kristen Stewart have become friends

The 'Liz & Dick' star - who is due to undergo her sixth stint in rehab in May - was introduced to the 'Twilight Saga' actress by a mutual pal and has had fun hanging out with her and her boyfriend Robert Pattinson.

A source said: "They met through one of Lindsay's friends who also knows Kristen. Lindsay was invited up to Kristen's house last week, and they hung out with Robert Pattinson, who was back from filming in Australia."

The two former child actresses have quickly discovered they have a lot in common.

The source added: "Lindsay and Kristen discussed their careers, creative ideas and how they deal with living under the focus of the media and the paparazzi."

Lindsay isn't the only famous star Kristen has been hanging out with recently.

The 'On the Road' star attended the Nickelodeon Kids' Choice Awards in Los Angeles with Katy Perry - who recently split from her on/off boyfriend John Mayer after seven months together - last weekend and the pair were described as having a great time.

The duo also spent time with Selena Gomez and pregnant Black Eyed Peas star Fergie but Kristen left her on/off boyfriend Robert at home.