The Harry Potter star, who plays a troubled young teen in Peter Shaffers psychological drama, also said that the duo got along well with each other, reports China Daily.
Daniel said: "We're getting on very well indeed.
I've written some really, really deeply sexual things on some of the cards I''ve given him for opening night. But just to wind him up, you know."
The 19-year-old, who bares it all during a scene in the play, further revealed that he would have loved to marry the 31-year-old had he been a female or a gay.
He said: "He''s a truly remarkable man. If I was gay or a female I'd just want to marry him.
He's gorgeous, and he's really cool bloke as well."