Britney Spears upcoming memoir includes an emotional account of what the star says is an experience shes kept private for half her life now.

In her book The Woman in Me, the pop star, 41, writes that she had an abortion 20 years ago after becoming pregnant with Justin Timberlakes child, People reports .

It was a surprise, but for me, it wasnt a tragedy, Spears writes in her memoir. I loved Justin so much. I always expected us to have a family together one day. This would just be much earlier than Id anticipated.

She added: But Justin definitely wasnt happy about the pregnancy. He said we werent ready to have a baby in our lives, that we were way too young.

Spears claimed the N Sync alum urged her to get the procedure.

Im sure people will hate me for this, but I agreed not to have the baby, Spears wrote. I dont know if that was the right decision. If it had been left up to me alone, I never would have done it. And yet Justin was so sure that he didnt want to be a father.

To this day, its one of the most agonizing things I have ever experienced in my life, she continued.

A representative for Timberlake did not immediately respond to HuffPosts request for comment.

Spears began dating Timberlake in 1999 when she was 17 and he was 18. The pair first met when they were kids starring on The All New Mickey Mouse Club.