Caitlyn Jenner reflects on 'mistakes' in first promo for ​new ​Diane Sawyer ​interview

Life has changed a lot for Caitlyn Jenner two years after announcing her plans to transition to become a woman.

In a new promo for 20/20's upcoming special, "Caitlyn Jenner: The Secrets of My Life," the former Olympian sits down with Diane Sawyer for a follow-up interview to her 2015 ABC News special.

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"Have I made mistakes? Certainly," Jenner says in the sneak peek, when Sawyer asks if she's ever had "doubts" about if she's doing the right thing.

See photos of Caitlyn Jenner:

Watch the promo HERE.

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"Caitlyn Jenner: The Secrets of My Life" with Diane Sawyer will air Friday, April 21, at 10 p.m. ET/PT on ABC. Jenner's upcoming memoir, The Secrets of My Life, will be released on April 25.

See more on the biggest revelations from Jenner's 2015 20/20 interview in the video below.