Nick Grimshaw confirmed on his Radio 1 breakfast show that the boyband will be kicking off the proceedings at the free two-day event, which takes place on May 24 - 25.
They said: “We're so excited to perform at Radio 1's Big Weekend in Glasgow. Glasgow we're coming to get you!”
Lily teased fans about her festival performance, saying: “I've got some exciting surprises in store about the way the show is being presented. It's been a long time coming, I'm very excited.”
Meanwhile, it looks to be a busy weekend for One Direction who will open up the event on May 24 and then head to Dublin, where they’re scheduled to play a stadium gig as part of their ‘Where We Are’ tour, which kicked off in South America last week.
The boys look like they’re having a great time out there, though admittedly band member Liam Payne seems slightly overwhelmed by the attention from the group’s South American fans.
He posted a picture to Twitter showing the magnitude of fans who were waiting for One Direction outside of their hotel room, writing: “I will never understand, and you will never understand what this does to somebody ...why?”
Tickets for Radio 1’s Big Weekend have now been allocated, though the event while be streamed live on Radio 1, 1Xtra and BBC Three.