It's been the Geri and Jerry show in London as the pair quickly became bosom buddies and have been seen larking about town together. Jerry's fiancee Giuliana is understandably upset about his spicy activities.

Geri Halliwell's lovelife has been less than spicy recently. But now she's making up for lost time - by falling for a man who's already engaged.

Geri jumped head first into a hot romance with Kangaroo Jack star Jerry O'Connell just weeks ago, soon after he arrived in London to co-star with her in a movie. Since then the pair have been seen in passionate clinches at posh London nightspots, with former Spice Girl Geri, 31, telling pals he could be her Mr. Right.

And in the strongest indication that their romance is more than a fling, Jerry introduced Geri to his parents over dinner at the chic London restaurant San Lorenzo.

But it seems Jerry, 29, made no mention of one important fact: he got engaged in May to his long-time girlfriend E! News Live shobiz reporter Giuliana DePandi. And Giuliana was less than happy when contacts told her about her fiancee's activities.

"Giuliana is very upset," says a friend of the TV presenter. "They have been dating for a year and have been very happy. Jerry is the man she was going to marry as far as she's concerned. Now she wants to know what's happening."

Geri is just as confused, say pals. Sources on the set of Fat Slags, based on a UK comic strip, say Jerry was instantly fixated - especially with Geri's bosom.

"He was amazed they weren't false," the insider says. "The girls that size in Hollywood are plastic."

Within days of meeting the pair went out for a boozy date, pawing each other during a West End show. They moved on to dinner and a karaoke bar, where Geri serenaded her new man with old Spice Girls tunes. Days later, they were happy to pose outside San Lorenzo after their meet-the-parents dinner.

Geri hasn't exactly been lucky in love in the past, with Robbie Williams breaking her heart and a messy split with millionaire Damian Warner, who she met in rehab. Jerry's list includes Estella Warren, Sarah Michelle Gellar and Shannon Elizabeth.

"Geri really thinks a lot of him," says her friend. "The way she talks about him - it sounds like he could be the one."

Unfortunately for Geri, Giuliana's father Eduardo insists the wedding is on.

"Jerry and my daughter are together and they're engaged," he says. "Men do this sort of thing - it is in their nature. Giuliana will be upset by this, but I don't need to worry about my girl. She is a strong woman."