Time Inc
October 18, 2018 2:00 pm
Scott Kowalchyk/CBS via Getty Images

As far as massively popular book-to-screen franchises go, Game of Thrones and 50 Shades of Grey really couldn’t be more different. But when Jamie Dornan needed to run lines for his role as Christian Grey, Peter Dinklage had no problem stepping into the Red Room—figuratively, that is.

During an appearance on October 17th’s episode of The Late Show with Stephen Colbert, Dinklage revealed that while filming his forthcoming movie My Dinner with Hervé, he helped his co-star Dornan rehearse for 50 Shades by reading Dakota Johnson’s part in the script.

“I think that’s one of the lines,” Colbert quipped.

Watch the full clip below.