Comedian Jo Brand is setting off on a Sport Relief challenge which will see her walk 150 miles coast-to-coast, from Hull to Liverpool, in seven days.
The 58-year-old, who is starting her Hell Of A Walk challenge in Hull on Friday, says the week will be the biggest challenge of her life.
The former psychiatric nurse has said she wants to use the walk to highlight the work that Sport Relief does on mental health issues as well as raise cash for the charity.
Brand said at the launch of the event: "When I first started training for this challenge, I didn't realise I was not the national fitness icon I'd always believed myself to be. My body is a temple - it's big and it doesn't move.
"The realisation is gradually dawning that I have to walk a very, very, very long way, with many days back-to-back using only my poor little legs to carry me - and that's a gruesome thought.
"But the hope is that the walk will raise much needed funds for people who really deserve it, which will keep me going."
The BT sponsored challenge will see Brand climb to 1,500ft across The Pennines and take a total of 60,000 steps as she walks from dawn to dusk, burning around 6,000 calories each day,
Sport Relief said she will be joined by famous friends and people helped by funded Sport Relief projects along the route to spur her on.
Brand's journey will be recorded for a BBC documentary to be broadcast in the run-up to Sport Relief Weekend, which is taking place from March 18 to 20.