The two Brits were promoting their new movie at a junket in New York on Wednesday (29May13) when the actress was asked about her plans to return to the theatre - and let slip that she was planning to join her co-star onstage.
Riseborough told reporters, "I did a play in New York called Pride in 2010. I would love to come back and we've been thinking about something recently that I think would be pretty exciting. The only thing I can say is it might involve Clive and I again!"
Clearly not ready to make the announcement, a shocked Owen said, "She won't keep things quiet! There's nothing more to say, but, I've never had a Broadway debut. I did a lot of plays in London but never in New York."
The actor then quickly changed the subject and opened up about his theatrical past, recalling, "I trained in the theatre; I went to the Royal Academy for three years and the first thing I did was I toured a play all over the place. My first play in London might have been Design For Living.
"When I first started that's all I wanted to do was the stage. I'm very lucky with the way things have panned out. I love making movies and I love it as much as the theatre now, more probably because there's something really special about the collaboration in a film."