"Our shows in London have always been amazing. They've always had amazing energy cos the fans here are awesome," Avril told CBBC Newsround Lite.
The young star also said how much she and her band loved being back in the UK: "It's really cool to be back here in London - we like it," she said.
Sell-out concert
Avril went on to perform at a sell-out concert at the Astoria and in front of a live audience of Radio 1 competition winners.
At one point during the Radio 1 gig she spoke to a fan on a mobile phone.
But after a couple of minutes she had to hang up, telling the fan she was a bit busy!
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