Caitlyn Jenner says she has become distant with some of her children since transitioning

Caitlyn Jenner has become distant with "a couple" of her children since she came out as transgender, she has revealed in an interview.

The former Olympic decathlon champion first came out as transgender two years ago and has said that since then she has seen some of her children drift away from her.

Jenner, 67, 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 instrumental in raising Kris's children from her first marriage - Kim, Khloe, Kourtney and Robert Kardashian,

Caitlyn Jenner at the 27th Annual GLAAD Media Awards.Credit: Getty Images

In an interview with Diane Sawyer on news show 20/20, Jenner said the children still call her "Dad" and added the reality of her transition has been difficult.

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

"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?'"

Jenner also admitted some of the children had doubts about her debuting her new identity in a corset on the cover of Vanity Fair in June 2015.

Caitlyn Jenner's Vanity Fair cover in July 2015 felt like a watershed.

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, OK?

"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."

Jenner was speaking to Sawyer as she promotes her new autobiography The Secrets Of My Life.

However, her ex-wife Kris has spoken of her distress over what she claims are "made up" details in the book.

Kris, 61, denies Caitlyn's claims that Kris was aware of her desire to transition into a woman throughout their relationship and before they slept together for the first time.

PA