Grimshaw, who joined the station in 2007, has hosted the drivetime show since 2018.
Aled Haydn Jones, head of the station, said: “Grimmy has given everything to Radio 1 over the past 14 years and he is loved by all of us who’ve had the pleasure to work with him.
“He helped to define Radio 1’s young audience, is always supremely entertaining on air, and is an incredible radio talent. We wish him all the best but most of all – thank you!”
When is his last show?
Grimshaw announced at the end of June that he would be leaving his “dream job” at BBC Radio 1.
He said: “My childhood dream was to work on Radio 1 and I have been lucky enough to make that dream come true.
“It has been everything I’d imagined and even more. I grew up wanting to connect with people and to feel accepted and the Radio 1 listeners gave me that and let me be part of their daily life, for which I will be eternally grateful.
“But over the last few months I've been doing a lot of thinking about my future and after 14 years, I’ve made the decision that it's time for me to move on – I'd like to thank the listeners as without them none of this could have been possible and the Radio 1 family, who have been such a huge part of my life.
“Thank you, thank you, thank you."
His last show will be on 12 August, with his replacements taking over from 6 September.
Who is replacing him on BBC Radio 1?
Grimshaw will be replaced by radio presenters Vick Hope and Jordan North.
The pair will be co-hosting a new drive time show on Mondays to Thursday from 3:30pm to 6pm.
The two both have radio experience, with Hope hosting shows in the past like Life Hacks on BBC Radio 1 and Capital Breakfast show on Capital FM, and North who currently hosts the weekend lunchtime show on BBC Radio 1, and having acted as the main cover presenter for Scott Mills and Grimshaw.
Speaking about the new role, Hope said: “What a madness! Drivetime!!!
“I love Radio 1 so, so much, having grown up tuning in religiously every single day. It means the world to be taking the reins at home-time with the phenomenal Mr North.
“Grimmy is an absolute legend of the game, thank you mate for every laugh you’ve sent rippling through the country!
“Taking over Drive is a take we won’t be taking lightly, but Jordan and I are ready to put our all into making your journey home that little bit brighter.”
North added: “I am absolutely chuffed to be making the move over to Radio 1 daytime and even happier to be working alongside Vick.
“Grimmy is a Radio 1 legend so we definitely have big shoes to fill but will work extremely hard to make sure afternoons on Radio 1 still sound superb.
“I am super excited to get started and look forward to this next chapter with Vick and the rest of my Radio 1 family.”
What will Grimshaw do next?
As of yet, Grimshaw hasn’t made any announcements for what he’ll be getting up to after his departure from Radio 1.
However, he has been quoted by The Sun as saying: “It’s a big decision but the right one - I feel excited. I want to do some telly stuff and have a think about what else.
“I’ve been doing a daily show for 12 years so I just need space to think about what I wanna do.
“You just spend every day going, what are we going to do on the radio, what are we doing tomorrow? It’s nice to have a little gap where we’re not thinking about that.”
Grimshaw has previously done TV work, appearing as a judge on series 12 of The X Factor, guest co-presenting The One Show on the BBC for a handful of episodes, and appearing on Celebrity Gogglebox.
He has also made guest appearances on shows such as Never Mind the Buzzcocks, 8 out of 10 Cats and The Great British Bake Off For Stand Up To Cancer.