Michael Bowen reveals the secret backstory for Todd he created with Jesse Plemons, how years of auditions with Dean Norris made it hard to kill Hank, and the "starvation diet" he underwent to look like a stringy ex-con.

[Warning: Spoilers ahead for the Breaking Bad series finale, "Felina."]

Breaking Bad ended with Walt (Bryan Cranston) dying peacefully after sending his enemies off in a blaze of glory. As Uncle Jack, Michael Bowen became the improbable antagonist of the series finale after he killed Hank (Dean Norris) and stole Walt's money in the instant classic "Ozymandias."

Bowen admits shooting his final Bad scene was tough, but says it was nothing compared to the emotional toll of killing Hank. He says he knew Norris from auditions back when they both were "going out for one or two lines, just trying to get some food on the table."

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On the day he shot Hank's death scene, those memories came back as he looked into Norris' eyes.

"I'm glad the camera wasn't on me, because my lip was shaking. I was about ready to cry. It really affected me," Bowen tells The Hollywood Reporter.

He also reveals that he and Jesse Plemons, who played his nephew Todd, created an elaborate backstory for their characters centered on the idea that Todd's mother had been a drug addict with a string of abusive boyfriends. The two agreed Uncle Jack had rescued Todd from that situation and raised him with the Aryan gang.

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"He'd bring something up [from our fictional backstory] and he would ask me a question within that context. I'd riff of that and he'd riff back," Bowen says. "We'd do that in the middle of the day or just randomly in the trailers to keep that going. Then you have all of those memories."

Find THR's full conversation with Bowen below, where he also reveals why he cheered when Todd died and the brutal regimen he underwent to drop weight for the part of the stringy ex-con.

How did you prepare to really look the part of this rough ex-con?

I got sick, I think. I know I depleted my body of vitamins. It was a choice, and it wasn't medically supervised -- and I think it might have been stupid. But it looked good. (Laughs.)

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What kind of things were you doing?

Anytime I was hungry I would fill my stomach with water. As for food, it would literally be a small piece of meat, maybe 2 inches in diameter. Nothing bigger than that. Then one or two vegetables. It was literally a starvation diet. I'm about 180 normally, and when I was doing Django Unchained I didn't want to have any 21st century fat on my body, so I started then and went down to about 167. I read for Breaking Bad and the look worked. I tried to stay at 163-165 the whole year that I worked on Breaking Bad. I wasn't very pleasant to live with. It made it difficult to fall asleep because I'd get these hunger pains in the middle of the night.

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Uncle Jack and Todd were very believable as family. What kind of things did you and Jesse Plemons do offscreen to prepare for this realistic family relationship?

He and I created a backstory that we would always talk about. We decided that Jack had a sister -- a drug addict. She had a revolving door of abusive boyfriends. She had a baby, little Todd. Some of them were abusive to him perhaps. I looked at him in this situation in which he would have no chance. As Jack, I think I killed more than a few of the abusive boyfriends. I got tired of doing that and I wanted to rescue the little guy, so I took him out of there.

You guys created this backstory just through conversations together?

He'd bring something up [from our fictional backstory], and he would ask me a question within that context. I'd riff of that and he'd riff back. We'd do that in the middle of the day or just randomly in the trailers to keep that going. Then you have all of those memories.

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Was it hard to say goodbye to Jesse Plemons after creating that bond?

The relationship is still there. I think the relationship never dies. We have great talks as Jesse and Michael. We talk about the blues. We talk about philosophy. That's never going to go away.

What scene did you have the most fun shooting?

When Jack and Kenny (Kevin Rankin) and Todd are in the diner after they wiped out Declan (Louis Ferreira) and his crew. Todd is telling his story, and I look at him as though I'm thinking, "Look how confident he is. Look at how happy he is." That, to me, was the proud father moment.

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You got to be on Breaking Bad until the end. What does that mean to you?

I was at the charity screening [at the Hollywood Forever cemetery] last night. I lost myself watching it. I was right there with the crowd when Todd got wiped out. I was yelling and screaming. You could hear the crowd reacting -- that means we did a good job. And when I got blown away and they clapped, I was very satisfied.

What was it like shooting that huge blowout scene?

It was very sad. You've created this family in a unique, creative environment on this great show. The last day was rough. It was a good day but it was a sad day. We shot it at three in the morning.

What was the hardest scene to shoot?

The scene where I kill Hank. On the paper I'm looking at it. "OK, OK, it's pretty hard. It's going to be what it is." But on the day, when that was getting close to happening, I was getting very emotional when Dean was talking to Bryan. And Bryan's saying, 'Please, please, please' -- he's pleading for Hank's life. And Dean knows what's happening. Just his eyes -- the clarity in his eyes. I'm glad the camera wasn't on me, because my lip was shaking. I was about ready to cry. It really affected me.

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Then, not long after, you have to be cheerful because you've found all of Walt's money.

I loved those types of moments with him. There were quite a few of those. He's just back to business, but in a funny way.

Why was it so hard for you to kill Hank, as an actor?

All of the stuff came flooding out. I've been in the game a long time, and I've seen Dean Norris on a lot of auditions. When we were going out for one or two lines, just trying to get some food on the table. And now he's got some success, and he's down on the ground and just kicking ass -- and his eyes are so clear.