Spencer Matthews says he wants to find his late brother's body for his mum, after he embarked on a mission to retrace his sibling's steps.
Michael Matthews disappeared on Mount Everest in 1999, when Spencer was just 10 years old.
His body was never found, but it is believed that he is one of the 310 people who died attempting to climb to the summit.
Michael was just 22 years old when he climbed the mountain, and became the youngest Briton to reach the top - before he vanished three hours later.
After finding it "unbearable" knowing that his brother's body was still on the mountain, Spencer decided to create a documentary of his search.
Ahead of the release of Finding Michael on Disney+, Spencer told The Sunday Times: "He's frozen in time. I'm his big brother now. I was unable to stop thinking about it. I wanted to bring him home for my mum."
Spencer filmed the documentary with the help of Bear Grylls and record-breaking mountaineer Nirmal 'Nims' Purja.
"I found the idea unbearable of him being out there on the mountain, alone, with people walking past him en route to the summit.
"I'm not the most emotional person but the nearer we got to the mountain, the more potent my feelings became. It's the closest I've felt to Mike since his death."
In a trailer for the documentary, Spencer is seen looking at a picture of his brother, who was wearing a red ski jacket at the time.
The former Made In Chelsea star said that he "hates" the picture because it reminds him of how close to death Michael was.
Spencer's family were sent a photo of a body, and he believes that it's his brother's.
In the trailer, Bear warned Spencer ahead of his trip to be careful, reminding him that around seven people die on Everest every year.
He told Spencer that "no mountain is worth dying a second time over".
He told Holly Rubenstein's The Travel Diaries podcast: "I was aching to find out more about his death. I was 10 at the time. I remember thinking it was really unfair.
"I always believed that I'd see him again and never took it on the chin that he was dead. I thought it was impossible. It never crushed me in the way it affected my parents and my brother.
"We would read that you could recover bodies from Everest. I know now that you can fly helicopters into Camp 2. For people who don't know Everest, that's quite a big deal," he explained.
Speaking of his plan, he said: "From base camp there is the Khumbu Icefall leading up to Camp 1. Then Camp 2 is at the end of a long plain right at the base of what you would think is the beginning of the climb.
"It makes it easier to bring bodies down – I mean it is not easy – it requires a lot of manpower, but getting them to Camp 2 can be done and then helicopter back down."
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