Thousands of music fans have rocked up to see Lady Gaga, JLS and Jessie J - plus loads more! - at the Children in Need Rocks gig in Manchester.
X Factor judge Gary Barlow's organised Thursday night's concert to raise loads of cash to help kids in the UK.
Marvin from JLS told Newsround's Leah it's "incredible to be asked by someone like Gary to be involved with tonight".
Kelly Rowland, N-Dubz's Dappy and Fazer, and Coldplay are also on the star-studded line-up at the MEN Arena.
So how does Gary Barlow manage to get so many huge stars involved?
He explained: "What you find is with a concert like Children in Need is that, as soon as people hear that name, that brand, they instantly drop their guard and go, 'Definitely, I'll be into that'."
The Take That star added: "Everyone I've asked has come on board, so its been incredible."