Strictly's Shirley Ballas has whizzed down a zipline to raise funds for a suicide prevention charity after her brother took his own life.
She completed the zipwire challenge at Penrhyn Quarry, Gwynedd, and now faces 700ft wing walk and 15,000ft skydive.
She said she could not sleep the night before, but in the moments before she could feel her brother was with her.
Ballas said the "terrifying" feats were for anyone who is suffering or had lost loved ones to suicide.
Speaking to Behnaz Akhgar on Radio Wales, she said: "You're definitely going to think I'm a bit strange but he was definitely there with me today.
"I felt he was holding me all the way and told me 'take a deep breath, I'm right with you'."
Her brother David took his own life in 2003 at the age of 44, leaving her and her mother "absolutely devastated".
Ballas, from Merseyside, is now working with mental health charity CALM - the Campaign Against Living Miserably - to raise awareness.
"I'm doing this for my brother who took his own life 20 years ago," she said.
She added the man who had harnessed her this morning had also lost someone to suicide.
"Messages are pouring in about people who've lost loved ones unexpectedly and people who know people who are living miserably so I'm doing it for everybody out there who are suffering.
"I didn't want to bake a cake or cut grass, I wanted to do something that was challenging for this great cause."
She said she wanted to highlight CALM's helpline service and also for people to look out for each other.
"We get so wrapped up in our own life which is something that happened with me with my brother that we fail to see signs which are often in front of us and to listen more," she added.
"If you feel that somebody is not doing well to reach out.
"You don't have to be over imposing but you can reach out and be a great ear to listen."
Ballas added she did not expect to get very much sleep while doing the challenges and the prospect of the skydive and wing walk to overcome her fear of heights were "terrifying".