Giuliana Rancic details her relationship with former flame, Jerry O'Connell, in her new memoir, claiming he cheated on her with a Spice Girls member.

Looks like the E! News co-anchor is giving fans new details about her past relationship with the "Kangaroo Jack" actor, Jerry O'Connell, who apparently wasn't so loyal in the love department, after all, E! News reported.

In her new book titled, "Going Off Script," television personality, Giuliana Rancic spilled secrets some her exes might have thought were part of a forgotten past.

Rancic dated O'Connell from 2003 to 2004. The two reportedly met at the W Hotel in San Diego and developed a special bond that immediately turned into something romantic. Things, however, turned when she found out O'Connell was cheating on her with Spice Girls member Ginger Spice, AKA Geri Halliwell.

According to Page Six, the Fashion Police host compares the actor to Jekyll and Hyde in her new book.

"I was being two-timed for one of the lesser Spices?" she wrote.

When she called his bluff, he said he was sorry and he didn't know what happened. The 40-year-old E! News co-anchor compared O'Connell's emotions to a customer-service representative "who tells you your bags missed the flight."

An apologetic O'Connell managed to woo her back and the two even discussed plans for marriage until the Maxim's 100 Hottest Women party in 2004. Rancic who was No. 94, states that he was at the VIP area that night talking up Rebecca Romijin, who was No. 7.

Just a week later, O'Connell stopped returning her calls and she confronted him at his home. He reportedly ended their relationship saying, "Things change, but you take care, OK?"

O'Connell married Romijin in July 2007 and they welcomed twin daughters in Dec. 2008, while Rancic is happily married to Bill Rancic and they have a 2-year-old son, Duke.

"Going Off Script: How I Survived a Crazy Childhood, Cancer, and Clooney's 32 On-Screen Rejections," hit stores on Tuesday, April 7.