In her upcoming memoir The Woman in Me, the pop icon, 41, reveals that when she dated Justin Timberlake, she became pregnant with his baby but had an abortion, PEOPLE magazine reported.

“It was a surprise, but for me, it wasn’t a tragedy. I loved Justin so much. I always expected us to have a family together one day. This would just be much earlier than I’d anticipated,” Spears writes of the pregnancy in the book as quoted by People.

“But Justin definitely wasn’t happy about the pregnancy. He said we weren’t ready to have a baby in our lives, that we were way too young," she said.

A representative for Timberlake did not immediately respond to PEOPLE’s request for comment.

She writes in the book: "If it had been left up to me alone, I never would have done it. And yet Justin was so sure that he didn’t want to be a father.”

Spears writes of her experience undergoing the abortion: “To this day, it’s one of the most agonizing things I have ever experienced in my life."

Spears and Timberlake split in 2002.

She became a mother to two children with her second husband Kevin Federline- Sean Preston, 18, and Jayden James, 17.

Ahead of the book’s release, sources told Page Six exclusively that Timberlake, 42, had been “concerned” about what Spears, 41, was going to share from their relationship.

“It’s eating at him,” one insider shared Monday, while another insisted the tell-all was “not a takedown” of anyone in particular.