Jerry O'Connell's cheeky response to ex Giuliana Rancic's cheating claims

Giuliana Rancic isn't going to be happy about this.

Her ex Jerry O'Connell has finally responded to her claim that he cheated on her with former Spice Girl Geri Halliwell, and he doesn't seem to be taking it very seriously at all.

"We dated, then we didn't date," he said on Watch What Happens Live.

Check out the video above to hear what else Jerry, 41, had to say about Giuliana, 40. We get the feeling the bad blood might run on both sides.

In her autobiography Going Off Script, Giuliana claims Jerry showed no remorse when she confronted him about the alleged affair.

"He had as much emotion as the customer-service representative who tells you your bags missed the flight," she wrote.

She also wrote that he later cheated on her with his current-wife Rebecca Romijn, 42, who was previously married to Full House star John Stamos, 51.

On Watch What Happens Live, Jerry also shared a funny story about how his six-year-old twins Dolly and Charlie reacted when they saw photos from Rebecca and John's wedding.

"My kids really want to know why Mom isn't still with him," O'Connell continued. "'That was a mistake, Mom.'"

Out of the mouths of babes…