Law & Order: Los Angeles Law & Order: Los Angeles

After spending the summer playing Nelson Mandela for the upcoming film Winnie, Terrence Howard just couldn't let go of the South African president-activist so easily. So he found a way to bring Mandela to his newest role, Deputy District Attorney Jonah "Joe" Dekker on Law & Order: Los Angeles.

"The most important part of him was his legal appetite and his appetite for moral rightness. When we finished the movie, I wasn't finished being a lawyer," Howard told reporters on a conference call Tuesday.

Law & Order: Los Angeles' Terrence Howard says character is show's "moral compass"

Added executive producer Rene Balcer: "He did the read-through in Nelson Mandela's voice. That was quite an experience to hear Nelson Mandela read those lines."

Although Howard first made his mark on the small screen on the short-lived sitcom Sparks and in memorable music videos such as Ashanti's "Foolish," he's spent the bulk of his career in film. After his Oscar-nominated breakthrough role in Hustle & Flow, Howard has appeared in such summer popcorn fare (Iron Man) to adult dramas (The Brave One).

But it was after a chance encounter with friend Reese Witherspoon a few years back that made him rethink his career path. "She said, 'You're doing too many movies.' It was true, I was just jumping on to whatever I could jump on because I just wanted to keep working," Howard said.

Check out photos from Law & Order: Los Angeles

With Law & Order, he sees a chance to "keep up the craft" while also doing movies intermittently, a possibility since Howard is splitting the role of DDA with Alfred Molina.

Once he signed on, Howard had an eclectic group of resources to draw from the part of Dekker. He talked to friends in law school who studied Law & Order in class and Los Angeles area prosecutors and judges.

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It also helped that Howard had multiple Law & Order veterans on speed-dial, including S. Epatha Merkerson and Jesse L. Martin.

The biggest inspiration, however, came from Supreme Court justice Thurgood Marshall.

"Thurgood had a real soft spot, but his belief in principle overweighed any amount of unnecessary mercy," Howard said. "My character, Dekker, doesn't want people to be found guilty. What he's hoping is that the defendant will prove their innocence. He just wants the truth."

Also just like Marshall, Howard said everything goes straight to Dekker's heart. "I ended up breaking down and crying while I was questioning someone on the stand," he said.

That part of the episode, airing Wednesday, didn't make to the final cut.

"We're holding that for ransom," Balcer joked.

Howard makes his Law & Order: Los Angeles debut Wednesday at 10/9c on NBC.