Chastity Bono

Chaz (né Chastity) Bono, the 40-year-old daughter of Cher and the late Sonny Bono, is undergoing a gender change — a transition that began shortly after his birthday earlier this year, his publicist said on Thursday.

"Chaz, after many years of consideration, has made the courageous decision to honor his true identity," Bono's publicist, Howard Bragman, said in a statement. "He is proud of his decision and grateful for the support and respect that has already been shown by his loved ones."

"It is Chaz's hope that his choice to transition will open the hearts and minds of the public regarding this issue, just as his coming out did. We ask that the media respect Chaz's privacy during this long process."

Now a civil rights advocate, journalist and author, Bono came out to his parents at age 18, then went public in 1995.

In the book Family Outing: A Guide to the Coming Out Process for Gays, Lesbians, and Their Families, Bono recounted how his mother "went ballistic for a few days" after learning of her child's sexuality, yet soon came to terms with the news and became an advocate for the LGBT community.

Disparate political views ultimately estranged Bono from her father, who had followed up his career as an entertainer by becoming a Republican congressman. The two had not spoken for more than a year when Sonny died in a January 1998 skiing accident.

As a little girl, Bono was a regular on the 1970s variety series The Sonny & Cher Comedy Hour. In 2005, Bono competed on VH1's Celebrity Fit Club 3.

Bono's writings also include the memoir The End of Innocence, which in part discusses Bono's partner, Joan, who died from non-Hodgkin's lymphoma.