As the star is now 40-years-old, Mario Lopez says it's time to open up about his life and has written a memoir titled "Just Between Us."

"I turned 40, and that's an important age for a man, and I think when you hit 40 it's time to sort of pause and reflect on how you got there and to help make a mature plan for the future and I [thought] what better than write it down," Lopez said in an interview with Fox News Latino

The memoir dives into many different aspects of the actor and television host's life.

"I feel like you need to be completely honest, and unfiltered and put it all out there, and I did," Lopez said. "Everything from my romantic life, my love life to my professional life, where I come from, being a child of immigrants, being born and raised in Chula Vista."

Amongst the detailed stories is the tale of Lopez's obsession with sex as a young teenager.

"I started having sex so young; the day before my 13th birthday," he told People. "Now that I'm a Dad, I look back and I think, 'Oh my God!' But you've got to understand, when you're growing up in the hood, everybody grows up fast." 

In fact, he had his first pregnancy scare at 15-years-old. He planned on getting a full-time job to support the baby's mother and the child, but the mother eventually had an abortion.

Lopez also shares juicy details about life in Hollywood, including his first kiss, which happened to be with Black Eyed Peas singer Fergie (they were on "Kids, Incorporated" together), getting romantic with "Saved by the Bell" co-star Tiffani Thiessen and his two-week-long marriage to Ali Landry that ended after the former Miss USA saw racy photos from his bachelor party.

"I got inebriated and a little too friendly with a young lady," Lopez wrote in the book. "When it was time to return home, lighting hit me with the truth: I wasn't in love. But I walked down the aisle."

According to Page Six, "Just Between Us" also praises Sandra Bullock, Tom Cruise, Hugh Jackman, Will Smith and Denzel Washington for being "the epitome of genuine people," as well as complimenting Al Pacino and Cher's friendliness.

Lopez is much less kind toward Tiger Woods in the book, however. The golfer reportedly refused to take a photo with Lopez and was thus a "sort of a textbook 'how not to be gracious,'" Lopez wrote.

---

Follow Scharon Harding on Twitter: @ScharHar.