It's not often a major pop star takes time out to visit their fans - especially when their fans are still at school.
But that didn't stop Pixie Lott from surprising pupils at a school in Surrey with a very special concert. Ricky was there to get all the behind-the-scenes gossip.
"Children at Amesbury School are big Pixie Lott fans. Earlier in the year they re-made one of Pixie's music videos and posted it online. Since then, it's clocked up more than 250,000 hits.
Pixie saw the video after her mum sent her a link and she became an instant fan.
To show the children how much she loved their version of 'Boys and Girls', she made a special visit and even sang a few of her hits - and of course Newsround got the exclusive.
Watch the full video here!
It was definitely a jaw dropping moment as 19-year-old Pixie walked on to the stage. The children had no idea she was going to turn up!
Pixie told me that she couldn't believe how professional the video looked.
"I thought it was fantastic. It looked so professional and it instantly put a smile on my face."
The real stars of the show were the children who recorded the video. Here they are with Pixie - she's not much bigger than them!
The students made the video to raise money for the Cardiac Risk in the Young (CRY). A couple of years ago a pupil at the school died of a rare heart condition.
The song is available to download and all the proceeds will be going to the charity.
The video is still a big hit online
but I think it's Pixie Lott who might be watching the video again and again and again