Gary Oldman on Why He Thinks He Was Just 'Mediocre' in Harry Potter Series

"I think my work is mediocre in it," he said of his fan-favorite performance. Oldman portrayed Harry's godfather in Harry Potter and the Prisoner of Azkaban, Goblet of Fire, Order of the Phoenix, and Deathly Hallows, Part 2.

The prolific actor also broke down just why it is he thinks he perhaps wasn't bringing the best take to the character. A colleague he feels got it just right was the late Alan Rickman, who brought Professor Severus Snape to life across all eight films.

Oldman broke it down on the latest Happy Sad Confused podcast, saying it was all about how much preparation he and Rickman did -- or more specifically, what RIckman did, and he chose not to do. Rickman reportedly also got inside intel from creator J.K. Rowling herself about Snape's future.

"Maybe if I had read the books like Alan, if I had got ahead of the curve, if I had known what’s coming, I honestly think I would have played it differently," Oldman said. At the same time, the actor admitted it's not just Harry Potter he struggles with when it comes to his own work.

"I’ll tell you what it is, it's like anything," he said. "I think if I sat and watched myself in something and said, ‘My God, I’m amazing,’ that would be a very sad day, because you want to make the next thing better."

He also said that part of it is the subjectivity of art; everyone experiences it differently and that's especially true for the artist. "It’s not to disrespect someone who says to me, ‘Oh, I really love you in that movie,’ and I’m thinking, ‘I’m terrible in that movie. What are they talking about?’ It’s not that. It’s they’re seeing something else."

While appearing on The Drew Barrymore Show earlier this month, Oldman said how grateful he was for the films' arrival -- along with The Dark Knight trilogy -- as they came just as he became a single father.

"At 42 years old, I woke up, you know, sort of divorced and I had custody of these boys," he told Barrymore, noting that the two franchises "saved me, because it meant that I could do the least amount of work for the most amount of money and then be home with the kids."

That doesn't mean it was all fun and games, though, with Oldman saying in this latest podcast appearance that one scene he filmed for the Harry Potter series was the worst thing he'd ever had to do in his long career as an actor.

The Academy Award winner was referring to a scene in Prisoner of Azkaban where the Dementors are sucking the soul out of Sirius Black's body alongside a frozen lake.

"It took forever. It was slow," Oldman explained. "What they did was they built this lake inside the studio, and they cooled it down and they froze this lake, and I had to just lie there for a week, day in and day out doing nothing."

He also lamented that his character was "killed off too early."

"I'm still upset about that," he added. "We were all taking bets. ‘It’s Hagrid,’ and I was there going ‘No no no, maybe it’s Ron,” and then you open the script and go ‘It’s me. I’m out of here.'"

While Oldman's character was killed before the book and film series  finales, he did get the chance to return for a cameo in the final film.