While the Olympian has not yet confirmed the transition rumours himself, his mum Esther Jenner appeared to do that on his behalf in an interview with The AP this week.
Esther said: "It was brief and I said I was proud of him and that I'll always love him. I never thought I could be more proud of Bruce when he reached his goal in 1976, but I'm more proud of him now. It takes a lot of courage to do what he's doing."
She admitted it had been a "surprise" when she first learned about the transition, saying Bruce broke the news to her by saying: 'I want to be honest about my identity and I know this is coming out in the press.' He started by saying, 'We need to have a long, serious talk.' I am at peace with what he is and what he's doing."
Rumours about Bruce transitioning into a woman have been around for the past year, fuelled by claims he's adopting a more feminine appearance. He now has long hair and has been seen with manicured nails.
Bruce, 65, has not spoken about the speculation himself but it's claimed he is currently filming an E! reality series which will focus on his decision to transition.
He's also said to be in talks with US news journalist Diane Sawyer about a tell-all interview, giving his side of the story.
Bruce is known to millions as an Olympic icon – he won gold in the decathlete at the 1976 Olympics – and, more recently, as a reality star thanks to Keeping Up With The Kardashians.
He split from wife Kris Jenner – mum to Kim, Kourtney and Khloe – in 2013, after 22 years of marriage. Kris and Bruce have two children together: Kendall, 19, and Kylie, 17.
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