Ouch! Brooke Shields threw shade at her ex-husband, tennis champion Andre Agassi, while discussing his wildly successful 2009 memoir, Open: An Autobiography, on Watch What Happens Live! on Thursday, January 14.

Agassi hired a ghostwriter, Pulitzer Prize recipient J.R. Moehringer, to write the tome, which included several memorable passages about Shields. A caller asked the actress what she really thought about Agassi's book, and her response conveyed plenty.

"Oh, I only read the parts I was in," the Lipstick Jungle alum, 50, replied. "I was asked to read it by him so that I could correct things that I believed were not correct, because he told me his memory was not that good. So he called me in and I spent five hours with his ghostwriter." With a smile, the Princeton grad chirped: "I write my own books, FYI. Anyway!"

Shields has written five memoirs and books of her own, including her November 2014 tome, There Was a Little Girl: The Real Story of My Mother and Me.

Shields said she made the appropriate tweaks to Agassi's memoir, only to find out later that she had wasted her time. "I corrected things that were not as I remembered them chronologically. I have diaries of everything," she explained. "Then I got a letter back that said, 'I'm so sorry I couldn't change anything because it wasn't how I remembered it.' It's the oldest trick in the book and I just didn't get it."

Luckily, Shields wasn't depicted in a terrible light. "With all due respect, I did not come across as badly as people might have thought that he wanted," she shared. "That's not who he is. He's not an evil person."

Shields and Agassi married in April 1997, and divorced less than two years later. In November 2009 on the Today show, Agassi opened up about his failed marriage to the supermodel. "I think at that time in my life I couldn't be married to anyone," he said at the time. "I think timing is really important. You need in a marriage, two people who understand themselves ... and I certainly didn't understand myself."

The Flower Shop Mystery: Mum's the Word star since moved on with TV writer Chris Henchy, with whom she has two daughters, Rowan and Grier.

Want stories like these delivered straight to your inbox? Sign up now for the Us Weekly newsletter!