Andre Agassi has a secret, and he's sharing: The tennis star has worn hair pieces for years! Not just subtle, low-key ones, but full-on '80s rockstar hair, mullets and more.

While it makes perfect sense -- in fact old photos scream fake hair when we look back -- we still felt a bit shocked by the now-bald star's admission, which he made via his upcoming book, "Open: An Autobiography."

According to an excerpt from the already-published German version obtained by the Daily Mail, during the 1990 French Open, Agassi prayed, "not for victory, but that my hairpiece would not fall off."

The bio also reveals scandalous details about Andre Agassi's family trouble, Crystal Meth use and numerous personal and professional struggles that were previously unknown.

At least the star has since sorted out his troubles (and hairstyle), found love and gained renewed respect on the court.

But really, we still can't get over the fact that he wore a wig!