Popular TV presenter Mark Speight has been found dead at a railway station in London, six days after he went missing.
The former SMart star had been having a bad time recently and his family and friends had been really worried.
In January, his girlfriend, Natasha Collins, died in their London flat after taking drugs.
An investigation looking into how exactly he died has started but the police don't think he was killed by anyone else.
Mark with his SMart co-presenter Kirsten O'Brien
People who were close to Mark have said they are shocked and devastated by the news.
They said he was hugely talented and caring, and loved by his family, friends, and everyone he worked with.
A month after Natasha's death, the TV star said he wouldn't be returning for the next series of SMart, because he was still so upset about her death.
His co-presenter on the show, Kirsten, told Newsround he was a big character and she was devastated to have lost him in such a terrible way.
"He had such a crazy take on life and he'd tell you these ridiculous stories," she said.
"And part of you would think, that can't be true, but then someone would go, 'No, that actually happened'.
"I really admired him on SMart for being able to simplify art and get kids into it.
"I think children really appreciated that and I was in admiration of that as a skill of having a gift, not just artistically, but in being able to communicate that to help others out as well."
If you would like to share any of your favourite memories of Mark, send them to us by clicking on the 'Mark Speight: Your memories' link on the top right hand side of the page.