Jennifer Aniston has praised her latest co-star Jason Bateman saying she believes his part in new flick The Switch is his best to date:

"I hope I'm not being biased but I really think that this is his greatest performance ever. It's hilarious, it's also moving and heartbreaking and I just think he's fantastic," said the actress.

The Switch sees Jennifer play a 40-year-old, single woman called Kassie, who is longing for a child, with Jason as her best friend Wally. When Kassie decides to inseminate herself and has a party to celebrate, Wally switches the sperm of her preferred donor with his own!

"For me I kind of liked the message that, I don't know that people will pick up on, but it's certainly what I liked, which is that a best friend is not necessarily a bad candidate for a long term relationship," said Jason.

"It's worked for me in my life, with my wife, so, that's kind of what this movie is saying," he added.

The Switch is out in the UK September 1.