Bruce Jenner tells Diane Sawyer his only concern is his family

"I can't let myself hurt them."

That's what Bruce Jenner tells Diane Sawyer in a new promo for his upcoming two-hour 20/20 special.

The reality star, and father of ten -- six biological and four step -- says his family members "are the only ones [he's] concerned with."

Audiences have learned very little about the exact subject of Jenner and Sawyer 's interview -- possibly on purpose.

NEWS: Is the Mysterious 20/20 Promo for Bruce Jenner's Sit-Down Interview Done By Design?

Rumors have been swirling for the past year that Jenner's changing appearance, including long hair and a shaved Adam's apple, means he is transitioning to a woman.

But daughter Kendall Jenner said the tabloid rumors were all "bulls**t."

Bruce Jenner has made no official statement regarding his gender or any planned transition. His mother told the Associated Press that he sat her down for a long talk and that what he told her was "a shock," but she was proud of him and would always love him.

In the new 30-second promo, a voiceover booms, "Bruce Jenner, on family" followed by Jenner saying, "Those are the only ones I'm concerned with. I can't let myself hurt them."

The voiceover says the interview will cover "the future, the decisions, the journey," but does not elaborate on what any of those entail.

A quote used in a previous promo is also repeated in this one: Bruce Jenner saying, "My whole life has been getting me ready for this."

The special will air Friday, April 24 at 9 p.m. ET on ABC.

Watch the first promo for the 20/20 interview:

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