Olivia Wilde and Jason Sudeikis are living together.

The couple - who have been dating for nine months - are "totally inseparable" according to friends but have no plans to wed as both have failed marriages behind them.

"They've both been married so they've already experienced that and know what it entails. It's something for down the road," a source told Us Weekly.

However, they are spending as much time together as possible, with Jason making sure he balances his work as a writer on Saturday Night Live with date nights with Olivia. "Recently, everyone on the show staff was writing late but Jason managed to sneak over to Radio City Music Hall to see Bon Iver with Olivia," the source added.

It was recently revealed the pair will star in Relanxious together where Olivia will portray an anxiety-ridden woman called Barrett who falls for George (Jason), an agoraphobic - a person with an intense fear of being in public places - so he can only speak to her over the phone. However, the couple eventually meet up and try to forge a real-life romance after a number of loved-up conversations where they plan fantasy dates.