Caitlyn Jenner has revealed that she has grown "distant" from a few of her children since transitioning to a woman two years ago.

The former Olympic champion and reality TV star first came out as transgender in June 2015 with a Vanity Fair cover, and now Jenner has opened up about her experiences since then in an interview with Diane Sawyer on the news show 20/20.

The 67-year-old has six biological children - Burt and Cassandra with first wife Chrystie Scott, Brandon and Brody with second wife Linda Thompson, and Kendall and Kylie with third wife Kris Jenner.

She was also instrumental in raising Kris's children from her first marriage - Kim, Khloe, Kourtney and Robert Kardashian.

Jenner has admitted that a couple of her children are "a little more distant" since she transitioned.

"Some [of my children] I have remained very close to. A couple of them ... I'm a little more distant", she said.

"I have to admit, I'll sit here and wonder, 'Is it because of my transitioning? Or is it because their life is so busy that they don't call, like, all the time?

"Nobody calls that much. I mostly reach out to them. Obviously the Jenner side calls more, but they all have their own lives."

Caitlyn Jenner and Kris Jenner

Jenner admitted that some of her children had doubts about her debuting her new identity in a corset on the cover of Vanity Fair, which was shot by legendary photographer Annie Leibovitz.

She said: "My feeling on that picture, I know, my kids that thought, 'You know what? It's a little too much', but from my standpoint, I had suffered for 65 years, okay?

"To have a beautiful shot of my authentic self was important. And the shock value... I wanted to end the old Bruce, my old life. And that picture did it."

Caitlyn Jenner debuted new identity on Vanity Fair cover

Jenner was speaking to Sawyer about her new autobiography The Secrets Of My Life.