Do you think it’s time for Castle and Beckett to finally hook up?
I don’t think it’s time to hook them up. I think that both of them have some deep-rooted issues they need to work through. No, I think it will really ruin the whole mystic if you do it, honestly. Keep them chasing that moment.

So tell us about “The Blue Butterfly.”
This episode is amazing. I can say, it’s my favorite by far. This episode is when Castle and Beckett are investigating the killing of a treasure hunter that actually is linked to a mysterious homicide that happens in 1947. So, Castle figures the way to solve that particular treasure hunter’s murder is to go back and solve the other murder form the past. The flash back scenes are—oh my God—amazing!

Your 1940's alter ego is a singer? Do you have a lyrical background?
Her name is Betsy and she is a chanteuse. She is the best friend of Dempsey, the gangster’s girlfriend. She sings, she’s wonderful.. I discovered through this episode that I have a lyrical background [laughs]...I really never sang anywhere else except the shower and the car but they told me it was a Billie Holiday kind of song I’d be singing and I love Billie Holiday...ask me to do Aretha Franklin or Patti Labelle and that would have been trouble, Billie Holiday I can do [laughs].

What can we expect the rest of the season on Castle, any reconciliation with Esposito?
I hope so, I felt like it looked like we would be in Ryan’s wedding episode but I don’t know. Those guys are real secretive in that writer’s room...so we’ll have to see.

You play a medical examiner, any experience with that until now?
Oh my God, it was so hard. I can tell you this season is the season I am the most comfortable playing Lanie and spewing those medical terms out. I am very grateful to the cast I work with because they have been extremely supportive and patient with me throughout the time that I wasn’t so comfortable.

Mark Pellegrino guest stars tonight. He’s coming off LOST playing a key role in Jacob.
He plays this bad gangster Tom Dempsey...The man is an amazing talent. I am a huge fan of his. I didn’t have any dialogue with him in “The Blue Butterfly,” but I was in scenes that he was there, and he’s just so strong, so handsome and so mean, but mysteriously mean.

Other than Castle what are some of your favorite shows?
I love Game of Thrones, I love True Blood and I love Boardwalk Empire...I love Dancing with the Stars, that’s one of my favorite reality-type shows to watch.. I love to dance and it just looks like they are having so much fun.

The Oscar nominees just came out, who are some of your favorites?
I hope that Octavia Spencer wins an Oscar as well as Viola Davis, but Octavia because we worked together in Blue Streak, she played my cousin and I’ve known her for years. I’m just so proud of her. And of course Meryl Streep. That’s my girl!

Check out all your Castle dish at ABC.

“The Blue Butterfly” airs tonight at 10 p.m. EST on ABC.

You can find Mike Rothman on Twitter @TheRealRothman.