Shirley Ballas broke down in tears as she talked about her brother’s death during her Comic Relief climb of Mount Kilimanjaro.
The Strictly star was one of nine celebrities who conquered the 5,895m (19,340ft) mountain for Red Nose Day.
During a BBC One programme about their trek, she revealed she took on the challenge in memory of her brother, who took his own life.
Not long into their journey, Ballas became emotional as they set up camp for the night.
Tearfully, she said: “I think my brother would be proud of me.
“I miss him, so I’m doing this for him. If it means sleeping in a tent and being disorganised for a week, I’m sure I can do it, I’ll do my very best for sure.”
Footage taken before the challenge showed the dancer meeting a man who had been helped by the charity Calm (Campaign Against Living Miserably), which receives funding from Comic Relief.
Ballas said of her brother: “My brother took his own life. He was a young man, 44.”
“He was like my brother, my father and my best friend,” she said.
“He was lonely, he felt low, he said he’d got into a dark hole he couldn’t get out of.
“I’d call him on the phone, ‘Come on David, you’re going to be fine’, because I was uneducated, so that’s why in some ways I blame myself.”
She added: “No note. No goodbye.
“I can only imagine 16 years ago if my brother would have had somewhere to go and somebody to talk to.
“I truly believe in my heart today he would still be here.
“And that’s why I’m climbing Kilimanjaro to raise awareness and help put a stop to suicide.”
The group also included Little Mix stars Jade Thirlwall and Leigh-Anne Pinnock, Love Island’s Dani Dyer, presenters Dan Walker, Anita Rani and Alexander Armstrong, former shadow chancellor Ed Balls and sports pundit Osi Umenyiora.
Kilimanjaro: The Bigger Red Nose Climb showed the group battling altitude sickness and freezing temperatures as they tackled the mountain.
Many said it was the toughest thing they had ever faced.
At one point Walker was so unwell with altitude sickness that he suffered some memory loss and he was told there was a chance he would have to go back down the mountain.
However, his condition improved and he was able to continue on to the summit.
The group were all emotional as they reached the summit, touching the sign on top of Kilimanjaro together.
Thirlwall said: “I’m so proud we did this. I bet nobody thought we could do it and we have. I’m really proud.”
Balls said: “There was always a question could we deliver and I think we are all feeling hugely proud and relieved because I think we did deliver.
“I think it’s been a monumental effort.”
Red Nose Day 2019 is on Friday.