Marvin from JLS has been talking to a group of kids about when he was bullied at school for wearing glasses.
The X Factor star also chatted about what makes him feel great and how music and catching up with friends keeps him happy.
It's part of a campaign launched by the children's charity Childline to try to get kids chatting about their emotions.
Marvin said: "Most people get bullied at some time in some form... but you should always tell someone."
He also talked about what helps him when he's feeling down.
Marvin from JLS is opening up about being bullied
He said, "I always put music on I like - I love music so I'm always listening to it, and I'll get on the phone to someone who'll make me laugh."
Marvin's not the only JLS star who's spoken out about their experience of bullying - Aston talked to Newsround for our bullying special, Whose Side Are You On?