Katy Perry was the surprise performer at Isla Fisher's 40th birthday.

The 'Now You See Me' actress has recalled how her husband Sacha Baron Cohen organised for the pop superstar to play at her 40th birthday bash three years ago, as she praised Katy for being ''so nice and sweet''.

Speaking on The Talk, Isla said: ''I turned 40 and ... I was putting on my makeup and [Sacha] came in and saw Katy Perry [branded] eyelashes, and he said, 'Oh, you really like Katy Perry.' I said, 'Yeah, you know that!' It was kind of a strange comment, but I didn't think of it again. Cut to I'm on the dancefloor, totally drunk with all my mum friends at my birthday, and I see like, a diamante microphone, and the hand gripping it is none other than Katy Perry! She didn't get paid, she's just so nice. She's so sweet and she sang all her hits, and I almost peed my pants, it was amazing!''

However, it was definitely different from Isla's most recent birthday as she hosted a games' night for her 43rd birthday bash.

She shared: ''I had sort of, 30 mates, and we hired this game company and they come and ... you do all these (games), Pictionary ... Charades, and all this sort of stuff. And my husband, who doesn't know anything about pop culture and is not sort of clued in, he won! And then when he won, he didn't even do a funny speech. He was like, 'Yeah, so?' He took home the present that I had bought for the winner! It was my birthday and he won!''