The two apparently hit it off but people had a tough time seeing them together in real life because of the different worlds that their respective fictional characters inhabit.
"Michael and I hung out a bit, and when we were together, it definitely freaked people out, because we didn't have trailers on this film set, so we were just hanging out on sidewalks and stuff,” Radcliffe said.
"People were walking by and going, 'Is that that Harry Potter guy and Dexter chatting over there?' I do think we freaked a few people out but, I like to think we sort of run blocking for each other."
The 24-year-old Radcliffe learned a lot from Hall.
"Also, it was nice for me to talk to Michael because he is in a much later stage in his career, and he'd done loads before he ever did Dexter, but he is in a similar position," he explained.
"He has a huge amount of attention for one thing. He probably gets called Dexter as much as I get called Harry Potter, so it's nice to just talk to him about that and see how he handles it, which is quite similar to mine. It doesn't really bother him. He's obviously very proud of Dexter, and I'm very proud of Harry Potter. But yeah, it's always nice to talk to somebody who's in a similar boat."
Hall will be also part of the all-star cast that will bring Will Eno's dark comedy, “The Realistic Joneses,” to Broadway. Toni Collette, Tracy Letts and Marisa Tomei will all also star in the play alongside Hall.