Family and friends have stepped up and spoken out in support of Bruce Jenner’s revelation that he is transgender, but perhaps his biggest supporter is son-in-law Kanye West.

NEWS: Bruce Jenner: 'I Am A Woman'

Jenner admits that the Kardashian sisters all had a hard time understanding his transition at first and that "they all cried" when he told them his truth. However, Jenner told Diane Sawyer in his sit-down interview on Friday with 20/20 that Kim's husband helped her come around to the idea.

"Kim told me a story," Jenner told Sawyer. "She goes, 'You know what really turned me around on thinking about this?' And I said 'What?' She goes 'Kanye.'"

"They were talking about it and he says to Kim, 'Look, I can be married to the most beautiful woman in the world, and I am. I can have the most beautiful little daughter in the world, and I have that. But I'm nothing if I can’t be me. If I can’t be true to myself, they don’t mean anything,'" Jenner explained. "Since then, Kimberly has been by far the most accepting, and the easiest to talk to about it."

As Jenner has not yet said that a new name or pronouns should be used, ETonline will follow GLAAD guidelines and continue to refer to him by his current name and male pronouns.

EXCLUSIVE: Kim Kardashian Speaks Out on Bruce Jenner: 'We All Support Him 100 Percent'

Kim talked to ET about Bruce earlier this week, saying the family was behind him "100 percent." See more in the video below.