In a case of childhood fantasies colliding, Emma Watson and Taylor Swift hung out in London over the weekend.

That’s right, the princess of pop and Hermione Granger are besties after meeting up at Swift’s huge Hyde Park concert on Saturday.

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The new friendship comes as no surprise as Swift has long been a fan of Watson (who isn’t?).

After Watson’s groundbreaking speech on feminism at the UN last year, Swift applauded the actress for clearing up the confusion.

“I wish when I was 12 years old, I had been able to watch a video of my favourite actress explaining in such an intellectual, beautiful, poignant way the definition of feminism,” Swift said on a French talk show in 2014.

“I just think that a lot of girls don’t know the definition and the fact that Emma got up and explained it, I think it’s an incredible thing and I am happy to live in a world where that happened.”

It appears as though the admiration is mutual: Watson was spotted by one hawk-eyed fan having a great time with friends at Swift’s London concert.

After the star-studded show – which also featured Swift’s celebrity friends Gigi Hadid, Karlie Kloss, Ellie Goulding, Cara Delevigne and Serena Williams – Watson and Swift, both 25, enjoyed a backstage hangout session.

The girl power party was documented in this Instagram photo, posted by British singer-songwriter and fellow Swift sister Lauren Aquilina.

In the happy snap Watson and Swift (middle) can be seen posing with (from left) models Martha Hunt and Karlie Kloss and musicians Sydney Sierota and Aquilina.

Swift, who recently took on industry giant Apple Music over a payment dispute, has a large group of female friends which also includes New Zealand teen sensation Lorde, the band Haim and actress Selena Gomez.