Little Mix star Jade Thirlwall has said her Mount Kilimanjaro climb was so “gruelling” there were times she did not think she could keep walking.

The singer was one of nine celebrities who conquered the 5,895m (19,340ft) mountain for Comic Relief on a trek when many of them battled altitude sickness.

Thirlwall said on Twitter the tough trek has changed her life.

Answering fans’ questions ahead of a documentary about the climb, she said: “There was a point when the altitude sickness was bad that I wasn’t sure how I was going to keep walking for hours and hours.

“On summit night, it was so gruelling I wanted to just fall asleep and be rolled back down but knowing why we were doing it kept me going.”

She added: “The altitude sickness is quite scary as it’s something I’ve never felt before.

“And on summit night I found it hard to breath which made me panic.

“It was so much harder than I thought it was going to be.”

The group also included Thirlwall’s bandmate Leigh-Anne Pinnock, Strictly’s Shirley Ballas, Love Island’s Dani Dyer, presenters Dan Walker, Anita Rani and Alexander Armstrong, former shadow chancellor Ed Balls and sports pundit Osi Umenyiora.

Thirlwall said she felt “euphoria, relief, pride, exhaustion, accomplishment and a whole lotta love for all the team” when they had completed the challenge.

“I have a better perspective on everything,” she said of life after the climb.

“It is honestly a life changing experience.

“And knowing more than ever where the @comicrelief money goes really made a difference in helping me to succeed.”

The ascent was documented for a special documentary which airs on BBC One later on Wednesday.

Red Nose Day 2019 is on Friday.