Former Downton Abbey star Dan Stevens has revealed that it was "extraordinary" to get to work with Liam Neeson in A Walk Among the Tombstones.

The actor, who can also be seen in acclaimed thriller The Guest, said that he was impressed with Neeson's attitude and work ethic on the set of the upcoming crime drama.

Stevens told Collider.com: "It's been an amazing year actually just working with a number of my childhood heroes - Liam Neeson, Ben Stiller for Night At The Museum, Adam Sandler in The Cobbler and John Travolta in Criminal Activities.

"Yeah, it is quite extraordinary, but what's really exciting for me is just seeing how these guys work, especially on Tombstones . . . Liam leads a great set. He takes the work very seriously. He's a total pro, shows up very cool, gets the job done."

The actor added that Neeson lightened the mood on set with jokes, saying: "I like Liam's way of working. He has a lightness off camera which keeps everyone in the right place. It's a very dark film, and if we were to inhabit that the whole time it could be a lot tougher than it was. He's a great guy to work with."

Read RTÉ Ten's interview with Dan Stevens here.