In a preview of the exclusive chat – due to air in the US on Friday – the 65-year-old tells Diane that he "can't hurt" his family.Â
Bruce said: "Those are the only ones I'm concerned with. I can't let myself hurt them."
The reality star has six children: Burt, 36, Cassandra, 34, Brandon, 33, Brody, 31, Kendall, 19, and Kylie, 17.Â
He also has four stepchildren from his marriage to Kris Jenner – former wife of celebrity lawyer Robert Kardashian – Kourtney, 36, Kim, 34, Khloe, 30, and Rob, 28.
Bruce Jenner Talks About Family in New Diane Sawyer Exclusive Promo
During his interview with Diane, the former-Olympian is expected to address rumours that he is transitioning into a woman.
It is thought his family are adjusting well to Bruce's new life.
It was confirmed last month that Bruce would sit down for an exclusive chat with the American journalist.Â
In the latest teaser clip, the former Olympian explains: "My whole life has been getting ready for this."
The eagerly anticipated TV special, entitled 'Bruce Jenner: The Interview', will be a two hour interview and will air on ABC on Friday, April 24.
In an interview on Entertainment Tonight in January, Kim spoke about her stepfather and their family support.
She said: "Well we support Bruce no matter what. Of course we support Bruce 100%."
Refusing to go into detail, Kim added: "He's our dad so we support him no matter what. And I think when the time is right, he'll talk about whatever he wants to talk about."
"It's his story to talk about, not really mine."