While Bruce Jenner confirmed that he was transitioning to female in an interview with Diane Sawyer in April 2015, his son Brody knew about Bruce's wishes as far back as 2012.
"You could just tell Bruce had some secrets," he tells HELLO! in an exclusive interview while promoting his new E! show Sex with Brody. "Obviously I couldn't tell how deep these secrets were, what Bruce was really hiding."
"But when my mother told me about three years ago, I think the first thing I said was,'I need a drink!'
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Brody has revealed he felt 'very relieved' when Caitlyn Jenner told him the truth
"I think that ultimately in that type of situation you want the person who is going through the struggle to tell you," he adds. "You don't want to bring it up with them, so I waited and it was awesome. I felt very relieved for him when he told me."
Bruce became known as Caitlyn Jenner after the transition and last week Brody joined siblings including half-sisters Kendall and Kylie Jenner and former stepsisters Kim, Khloe and Kourtney Kardashian in supporting Caitlyn as she received the Arthur Ashe Courage award at the ESPYs.
Caitlyn has received overwhelming support since making her stunning debut on the cover of Vanity Fair in June. Did Brody expect such a positive response?
"I had hopes for that," he says, "I wouldn't say I expected it. None of us knew what was going to happen, but all of us supported Caitlyn 100 per cent and said, 'Go for it'.
"I was blown away by the amount of support that was out there. It has been pretty inspirational to watch."
Brody is currently working as a producer and TV presenter on his new show Sex with Brody
The Jenners are no strangers to life in the public eye. Bruce won decathlon gold at the 1976 Olympics in Montreal, while Brody’s mother Linda Thompson is a lyricist and former actress, who also had relationships with Elvis Presley and music producer David Foster.
Brody has appeared on TV shows including The Hills and Keeping Up with the Kardashians. He is both producer and presenter on his latest TV venue, Sex with Brody, which took two years to develop.
The show covers various topics related to sex and relationships. His mother has been loyally watching the show, which he insists is not awkward. "My mother has seen it all," he laughs.
His model girlfriend Kaitlyn is also supportive. "She was a little nervous at first I think, but she has seen the show and sees it's lighthearted," he says.
While Brody has lived out much of his life on screen, he reveals that he doesn't want to be in the spotlight forever. "I think at some point I am going to throw in the belt and decide to stick behind the camera," he says.
* Sex with Brody is on E! at 11pm, Sundays.