Harry Potter's Gary Oldman thinks he was "mediocre" as Sirius Black

But Oldman surprised many when he went on to add: "I think my work is mediocre in it.

"No, I do. Maybe if I had read the books like Alan [Rickman], 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 continued: "It's like anything, 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."

Oldman starred as Sirius Black, Harry's godfather, in Harry Potter and the Prisoner of Azkaban in 2004, reprising his role in The Goblet of Fire, The Order of the Phoenix and The Deathly Hallows Part 2.

Oldman, who most recently has played the lead role of Jackson Lamb in Apple TV+'s Slow Horses, previously admitted that his involvement in Harry Potter and the Batman films saved both his career and personal life.

Appearing on The Drew Barrymore Show, Oldman said: "At 42 years old, I woke up divorced and I had custody of [my] boys. That was hard because there was a shift in the industry where a lot of productions were being [filmed in] Hungary, Budapest, Prague, Australia, you know, all of these places. So, I turned down a lot of work.

"Thank God for Harry Potter. I tell you, the two – Batman and Harry Potter – really, they 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."

For now, we have more Slow Horses to get excited about, with Oldman set to reprise his leading role. The series is based on the Slough House series of novels by author Mick Herron, with season 3 based on Herron’s novel Real Tigers.

The recently released episodes saw a romantic liaison in Istanbul threatening to expose a buried MI5 secret in London.

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