Nick Grimshaw is to trek 100 miles across a lake in Mongolia in aid of Sport Relief.
The BBC Radio 1 DJ is the first celebrity announced for the sub-zero four-day challenge.
The trek later this month will see eight celebrities cycle, skate and walk 100 miles across Lake Khovsgol, which is more than two million years old and freezes during the winter.
The challenge aims to break the ice on the stigma surrounding mental health issues and will be filmed for a BBC One documentary called Sport Relief: On Thin Ice.
It’s going to be really challenging both mentally and physically, but I can’t wait to get startedNick Grimshaw
Grimshaw said: “Super excited to announce that I’ll be doing 25 miles a day on ice in Mongolia all in aid of Sport Relief.
“It’s going to be really challenging both mentally and physically, but I can’t wait to get started!”
Newsreader and avid runner Sophie Raworth is also among the stars taking part in Sport Relief.
She will take on BBC Radio 3’s Beat Beethoven challenge, which sees members of the public run 5k around MediaCityUK in Salford and “beat” the music of Beethoven’s epic Fifth Symphony performed live by the BBC Philharmonic.
As part of this year’s TV entertainment, David Walliams, Davina McCall, Greg James, John Bishop and Gareth Thomas are among those who will share memorable moments from their fundraising challenges over the years in a special documentary.
Gymnast Max Whitlock, a double Olympic gold medallist and 2019 world champion, will be announcing a new competition that will see him visiting one lucky school.
Whitlock has also joined forces with fellow sports stars Ellie Simmonds, Harry Kane and Jessica Ennis-Hill to launch this year’s official Sport Relief range, sold in Sainsbury’s and selected Argos stores.
The Sport Relief television show will be on BBC One on March 13, with Gary Lineker and Paddy McGuinness returning as hosts.
Sport Relief-themed TV shows, including Catchpoint, Blue Peter and Bargain Hunt, will also be aired.
Rio Ferdinand is one of the stars who has spoken out about as the initiative unveils its 2020 programme.
The former footballer, who lost his first wife to cancer in 2015, said: “Sport has this amazing ability to bring people together and tackle really important issues like mental health stigma, which I’m really passionate about.
“Sport gives you something to focus your energy on, and speaking from my own experiences off the pitch, it’s positively impacted my family’s lives when going through some hard times.”
Sport Relief raises money for issues including mental health, domestic abuse, homelessness and child poverty in the UK and around the world.