WATCH: Saoirse Ronan Sang Fairytale Of New York And Drank Guinness With Jimmy Fallon

Saoirse Ronan got seriously into the festive spirit on The Tonight Show With Jimmy Fallon this week.

The Irish actress joined host Jimmy on the show to promote her new film Mary Queen Of Scots and took the opportunity to sing a festive classic while she was there.

Saoirse and Jimmy sipped on pints of Guinness before breaking into 'Fairytale Of New York' by The Pogues and Kirsty MacColl.

After Saoirse tells Jimmy all about Irish pub lock-ins, he replies, “I was hoping we could have a Tonight Show lock-in right here, right now.”

They did a pretty good job, too – even Jimmy’s attempt at imitating Shane MacGowan’s raspy Irish accent was actually fairly decent.

You can watch their rendition for yourself here:

It’s a far cry from Saoirse’s appearance on Saturday Night Live when she faced a fair amount of backlash for her bizarre Aer Lingus sketch.

READ MORE: RTÉ Reveal Christmas Movie And TV Schedule And Everyone Is Going To Tune In For These Class Irish Documentaries