Chris O'Dowd has revealed that doing improvisation on his new TV show, Family Tree was "terrifying".
The Bridesmaids star portrays unemployed and newly-single Tom Chadwick in Christopher Guest's BBC Two drama, which is completely unscripted.
"It was terrifying. It's hard to be funny and be very naturalistic, and to be informative and move the plot along. It's a tricky trick to pull off, but it's always exciting, which is great," he said.
"You don't ever have to struggle with badly written lines, which is helpful, but you have to struggle with having no lines. You have to be focused all of the time, which really got in the way of my drinking," he joked.
Chris added: "I love a bit of improvisation and because this is an improvisation piece I thought it would be a challenge. One of the big draws of this project was that I hate learning lines - it's so boring and it felt like this would be different - there isn't anything else like it on TV at the moment so I was interested in it because of that."
The 33-year-old Irish actor also joked that Rihanna could make an appearance on the show.
"Rihanna is the one that naturally springs to mind, because I know she's got a lot of live improv in her background. Rihanna would probably play a version of herself because although she's very funny, she doesn't have a lot of range," he said.
Family Tree premieres at 10pm on BBC Two on July 16.