In one of the station’s biggest ever shake-ups, the weekend will officially start a day earlier as of June.
It means Grimmy’s breakfast show will now be presented by Saturday and Sunday hosts Dev and Alice Levine from 6.30am-10am.
Scott Mills will then front a rebooted version of the Official Chart Show from 4pm-7pm, as he counts down the nation’s biggest songs that week.
Mollie, who enjoyed a guest stint co-hosting Matt’s Saturday show earlier this year, said of joining the station: “I’ve grown up listening to Radio 1 and I can’t wait to be one of the team. This is an absolute dream for me!
“The only person more excited than me is my mum - who is delighted I finally have a proper job!
“I’ve had so much fun working with Matt over the past few weeks, and I’m so glad I’m no longer just ‘Mollie From The Saturdays’ but Mollie from the ‘Fridays, Saturdays and Sundays’!”
Radio 1’s new Friday schedule
6.30am-10am - Radio 1’s Weekend Breakfast with Dev and Alice
10am-1pm - Radio 1’s Greatest Hits with Maya Jama
1-4pm - Matt and Mollie
4-7pm - The Official Chart with Scott Mills
New Official Chart Show host Scott added: “I was sat with my Mum when I got this news, and she actually cried because I’ve been pretending to do the chart show on Radio 1 since I was eight years old.
“I’ve filled in on the show so much over the years, and I can’t believe it’s actually mine. I’m beyond excited!”
The changes come after broadcast regulator Ofcom ruled the station needs to play more “new music” during its daytime shows.
Radio 1′s new Friday schedule will begin in June.