You’re in a cast with Nathan Lane, Matthew Broderick and all of these hilarious Broadway pros. Is that intimidating?
Rupert Grint: It’s really intimidating, yeah. Just to keep up with them has become my main objective. They’re just so funny and they’re so experienced. They really know what they’re doing. It’s amazing to me to watch that. I’ve learned so much just being in the room with them.

Who cracks you up the most in rehearsal?
Rupert: Oh, Nathan is quite a force. He's hilarious, and Murray as well. I'm just so lucky to be surrounded by these people.

Tell me about this guy you’re playing, Frank Finger.
Rupert: It’s a type of character that I’ve never had the chance to play before—he’s someone very complicated and deeply troubled. That’s really what attracted me to him. The play is amazing, it's so funny and such an interesting insight into the theater world from behind the scenes.

You starred in Mojo in the West End. Did you pick up any tips you want to remember for this time?
Rupert: That was different because it was my first ever taste of theater in any form, really. Before that it was just school plays and pantomimes, so it was a big learning experience. [Mojo and It's Only a Play] are very different shows. But I find keeping the concentration quite hard, just being in character for so long. I’m used to dipping in and out. On a film set you’re in character just for a few seconds, then you walk away. So with this, you have to be in the moment for the whole two hours, so it’s hard, but it’s great fun.

Is this your first time living in New York?
Rupert: Yes, and I love New York. I've only ever been here for like two weeks at a time, so I never really got to know the place, but I'm loving it. It’s such a great place. I went to a Yankee game the other day.

The Harry Potter wizards are all getting on the Broadway train—you, Daniel Radcliffe, and now Tom Felton wants to. Why do you think that is?
Rupert: New York just feels like the place to be. I’ve seen some amazing shows here, and there’s such an incredible energy to the city. It’s so exciting, even just walking down the streets. The West End is great as well, I love that, but New York City a really special place.