David Costabile, who plays Gale Boetticher on AMC’s Better Call Saul and Breaking Bad, discusses bringing back his fan-favorite character, how he’s different than the Gale we knew from Breaking Bad, and how hard it is to learn to sing all those songs.

Q: When Better Call Saul first began a few years ago, did you hope there would be an opportunity for you to play Gale again?

A: I was excited just as a Breaking Bad fan to see more of the story and hear Peter [Gould] and Vince [Gilligan’s] voice to continue to live through whatever characters they wanted to make. I’ve certainly watched since the beginning. Funny enough, I was in Albuquerque while they were shooting the very last episode of the first season. I ran into Peter and we had breakfast. We were talking about old times and he said it would be so fun to have me on the show. I had never really considered that could or would happen. The character is incredibly fun for me to play. I loved playing that character. I was probably sadder than anyone else when Vince told me I was going to get shot in the face. I loved being on that show.

Q: When did you first hear about the opportunity presenting itself in Season 4? What was your reaction?

A: I was excited that they wanted to bring ol’ Gale back. I thought the introduction was very clever of bringing the song in. It’s an excellent song except for the fact that you have to learn the song. The task of learning the tune was mighty. I knew the tune from the beginning, but I hadn’t ever learned it. I also just thought it was a great reintroduction of who the character is. It’s super fun for Breaking Bad fans, but even if you haven’t seen Breaking Bad, you’ll know right away who they are and what they’re doing. You get the full flavor of all of those pieces. I had to walk around for weeks as a crazy person in New York City just singing this song over and over and over. [Laughs]

Q: The writers always seem to give you some difficult songs to sing. How did “The Elements” compare?

A: I would say they’re straight up the exact same – maybe “Crapa Pelada” [was harder] because I was more nervous singing that song than I was singing this song. I sang “Crapa Pelada” probably 750 times and I probably sang this song about 500 times. You have to lock it into long term memory and I feel like both of those songs are locked in there. I really wanted to do the whole song. In terms of how we were shooting it, there was a time constraint so we couldn’t do it every time. I had always wanted to do the whole song because I knew the song. We had created this experiment that would fit the tune so that his entrance would fit through the whole song. The scientists on set were there to guide us through what he could do. In a way, you want to mirror “Crapa Pelada” – that he’s watering the plants, making the tea and getting ready. That he’s at home at work like he is at home.

Q: Did you enjoy these songs better than “Major Tom” karaoke video?

A: [Laughs] Oh god! So painful. This song was more fun because I was alone. When we shot “Major Tom,” it was in front of a green screen and I was pretending to be in a karaoke bar. So, I’m pretending to read the lyrics as it’s coming through. The entire crew decided that they were all going to take their time out and watch. And it’s a long song. You see at the end where I’m so tired. It really was like, “Oh my God. This is going on forever” and everybody’s just standing around with their arms folded and laughing. So, that one was the hardest of them all, that is for sure. I think there’s a little bit of a sadist in both Peter and Vince once they found out that this is a skill of mine.

Q: How different, if at all, is Gale at this point in the story from the guy we saw in Breaking Bad?

A: I think it’s the beginning of his story in terms of feeling like aspects of his dream have been let down. I don’t think he ever really got embittered by it, but I do feel like the disappointment he felt fuels his commitment to Gus. You get to see him at the beginning of that. For him, the reality of his chosen field has not shown its ugly side. If anything, he’s probably even more open than he was when we see him on Breaking Bad. He’s as optimistic as he can be about everything at this point.

Q: How would you describe Gale’s relationship with Gus at this point? Does he feel he owes something to Gus because of the scholarship opportunity?

A: Hopefully that’s in the scene – not just the dedication, but the trust he has in this person and that this person is, on some level, honorable. Gale wants to give him honor for trusting him and he wants to extend that back by doing a good job and working hard. I do think on some level, Gale really believes in a set of virtues rather than looking at it as illegal and immoral.

Q: How did the scholarship and other things we learned about Gale after his death on Breaking Bad inform your performance this time around?

A: When you work with these fantastic storytellers, either the way they reveal the story or the way the story is revealed to them comes over time. My personal commitment is trying to really listen to what the writer is saying. I really want to not just honor what they’ve written, but also listen to all the possibilities inside of what they’ve made. Once you box yourself in, there’s no possibility that there could be a twist or you might not know something. I feel like the better the writing, the more mystery is involved in terms of the reveal of who that person is because you don’t know who they can be. Once the puzzle piece comes to you, rather than feeling like, “Oh sh—t. there’s no place for this puzzle piece,” the puzzle’s always moving and grooving. It’s not static. You want the creation of a character to move that way. The creation of a backstory is less of a static piece than it is of a fluid piece. That’s the thing I hope for and want to find.

Q: Why do you think Gus rejects Gale when he offers to cook his meth? How disappointed is Gale?

A: He’s very disappointed. Gus is playing a long game. He’s a very methodical chess player and does not want to get tripped up too easily. For Gale, it’s not just the possibility of repaying this debt, but really a deep-held belief he has about exactitude and of making something fine. He believes so wholeheartedly that chemistry can do this. When he sees something that is inadequate, it’s appalling. He wants to right that particular wrong. He doesn’t understand why somebody would be so inept at making something that you could make so much better if you worked harder. That is essential to who that person is.

Q: How much did Breaking Bad impact your career? Do you get stopped by fans?

A: It depends on what neighborhood and state I’m in. I remember when I had gone to Ireland. They just couldn’t believe that Gale was walking into a pub. It’s always different wherever you go. I get stopped a little bit more now that Billions is on the air. Once Gale has reappeared, I think people will come out of the woodwork because people will be reminded of their experience of Breaking Bad. So many people caught up at the end to watch the whole thing and I was long gone by the time the show ended. It will be very fun to see how it goes after this reappearance from the dead.

Read a Q&A with Rhea Seehorn, who plays Kim Wexler.

Better Call Saul airs Mondays 9/8c. For the latest news and exclusives, sign up for the Insiders Club.