A source with direct knowledge told ET that Jenner talked about transitioning 30 years ago, and that by the mid-1980s Jenner had started hormone therapy, electrolysis and had plastic surgery to make his features look more feminine. Jenner found his own facial hair to be repulsive, the source told ET.
The pioneer transgender tennis player Renee Richard's 1983 autobiography, Second Serve, had a major influence on Jenner, according to the source. In 1986, the book was made into a TV movie starring Vanessa Redgraves that opened to critical acclaim and a Golden Globe nomination.
The source told ET that it was around this time when Jenner began exploring the option of reassignment surgery with doctors in Denmark -- but that he backed off shortly after he started seeing Kris Kardashian Jenner.
The Olympic gold medalist had breast reduction surgery and halted hormone injections, the source said. According to Jenner's 1996 self-help book Finding the Champion Within, Bruce and Kris first met in September 1990, quickly became engaged and then wed in April 1991.
Today, Dr. Phil praised Jenner for his courage.
"I am so happy for him," Dr. Phil told ET. "This is his body and his life, and he needs to do what he wants to do. It drains your spirit if you can't be yourself. He is freeing himself."
This comes as Jenner's 20/20 special with Diane Sawyer airs Friday, April 24, at 9 p.m. ET/PT on ABC. So far, the promos for the interview have been vague, but according to the Associated Press, this is intentional, as potentially "outing" a public figure as transgender before the person has a chance to publicly address the topic themselves is frowned upon.