Caitlyn Jenner reveals she's had gender reassignment surgery

In her upcoming memoir The Secrets of My Life, Caitlyn Jenner reveals that she underwent gender reassignment surgery earlier this year.

The 67-year-old Olympian writes that she had the surgery in January.

"The surgery was a success, and I feel not only wonderful but liberated," Jenner wrote.

"I am telling you because I believe in candor. So all of you can stop staring. You want to know, so now you know. Which is why this is the first time, and the last time, I will ever speak of it."

Radar Online, which first published the quotes, said that Jenner decided to undergo the surgery because she was tired of answering questions from the public on the issue and tucking in her genitals.

"So why even consider it?" Jenner rhetorically asked. "Because it's just a penis. It has no special gifts or use for me other than what I have said before, the ability to take a whiz in the woods. I just want to have all the right parts. I am also tired of tucking the damn thing in all the time."

Jenner's book arrives April 25, just days after ABC plans to air a follow up interview with Diane Sawyer.

(Related: Diane Sawyer checks in with Caitlyn Jenner two years after groundbreaking interview.)