'The most horrible thing I've ever had to do'

While the intimate moment wasn't in fact incest, the 35-year-old said it certainly felt like it.

In the final movie of the iconic franchise, Harry Potter and the Deathly Hallows: Part 2, Watson's character, Hermione, has to get close with one of her co-stars.

While, for the fans, the scene was a long time coming, that didn't make it any easier for Watson, or her co-star, Rupert Grint.

Grint, who played Ron Weasley, was like a brother to Watson.

Watson told Jonathan Ross in 2012: "We did the kiss two weeks ago, and it was the most horrible thing I've ever had to do.

"Not because Rupert isn't lovely, and there are millions of girls out there who would probably chop their left arm off to kiss him, but it just felt like incest. That's the only way I can describe it.

"The great thing about kissing is that you close your eyes, so it was fine when I was actually kissing him because I had my eyes closed. So I could not think about the fact that it was him.

"The worst bit is when we had to open our eyes and look at each other because then it was just like, and then we couldn’t keep going."

Watson spoke about the kiss again during the HBO reunion special, Return To Hogwarts, which came out in 2022, and it seems her feelings hadn't changed one bit.

“Obviously us kissing was the most horrifying thing either of us have ever had to go through”, Watson said. Grint had little to add, saying only, "yeah."

The scene, Watson revealed, was "meant to be this dramatic makeout, but we [her and Rupert] just kept laughing."

The kiss, she added, "felt wrong on every level", because her, Grint and Daniel Radcliffe "are so much siblings" having grown up together on the set of Harry Potter.

Radcliffe, who played the boy wizard, admitted he did nothing to ease the tension, saying he was a bit of a d***" about the whole thing.

"I did not make this better, because I've been told significantly that I was just being an absolute d*** about this and was like, 'I'm gonna come on set and watch you guys kiss,'" he recalled.

"I'm sorry about that, guys."

Watson added: "Everyone wanted to be on set for it. 'Cause everyone was like, 'This is gonna be good, guys'."