Katy Perry gets booed during a music festival in UK, and the booing was heard from none other than Taylor Swift's fans. As the jumbotron showed two quick flashes of Katy 's face, Tay's fans immediately booed the "Firework" songstress.

The Katy Perry boos took place following a video montage played during London's British Summertime Festival Saturday. The video was for a commercial promotion of U.K.'s 95.8 Capital FM.

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Swift was about to appear on stage for her Hyde Park concert in London, it just so happened that the radio station's commercial prior to her show included other musicians like Perry.

Other musicians promoting the station and were included in the video were Taylor Swift, Ed Sheeran, One Direction and Sam Smith, according to Gossip Cop.

As the video began, some Swifties were captured on video giving Katy Perry boos as her face was shown on the monitor. Naturally, Swift's fans cheered when the "1989" singer's face showed.

Seventeen seconds long, the footage showing Swift fans giving Katy Perry boos also showed Katy appearing on the screen twice, therefore Katy Perry got booed not once, but twice as well.

It has been known for quite a while that Swift is not on good terms with Perry. According to Swift, 25, Perry, 30, tried to sabotage her tour before. Then, she wrote "Bad Blood" which was allegedly a "diss song" for the "Roar" singer.

This didn't just begin a raging war between the two singers, but a feud with Swifties and KatyCats.

The video of Katy Perry getting bood was uploaded on YouTube, and naturally, Perry's fans responded to the backlash, many of whom called Swift and her fans "immature," reported Ace Showbiz.

Meanwhile, it was reported by Hollywood Life that Taylor's circle of influential friends has grown. Her clique now includes Martha Hunt, 26, Karlie Kloss, 22, Emma Watson, 25 and Kendall Jenner, 19.

As soon as Taylor's show ended on Saturday, she was spotted hanging out with Emma.

Lauren Aquilina, an aspiring pop star, also tweeted a photo of the two, with Taylor wrapping an arm around the HeForShe ambassador's neck.

"Spent tonight surrounded by badass girls and couldn't be happier about it," she captioned her tweet.

See video below to watch Katy Perry getting booed by Swifties in London.

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