Sam Riley loved working with Kristen Stewart in 'On the Road'.

The British actor takes on the lead role of Sal Paradise - who leaves his aunt's house in New York to go on a road trip across the US - in the big screen adaptation of Jack Kerouac's 1957 novel and he Kristen who plays disaffected drifter Marylou is "a really cool girl".

He said: "Working with Kristen was great - she's a fantastic actress and a really cool girl."

Although Sam loved working with his co-stars - who also include Amy Adams, Viggo Mortensen and Garrett Hedlund - he admitted he was worried about taking on such an iconic role but felt he couldn't turn down such a great opportunity.

He told BANG Showbiz: "I don't know when it's coming out but I'm excited about it. I was a bit scared taking on such a big role. I don't know why though because I kept asking for it.

"If you get offered a part like that you can't say no to it no matter how intimidating it is."