A pregnant Lauren Silverman got frisky and groped Simon Cowell's butt as they returned to the UK from their vacation in France. Sources say Lauren Silverman will meet Simon Cowell's mother while back in London.

Perez Hilton reports that Simon Cowell and Lauren Silverman made their way to their London home after returning from their Saint-Tropez vacation. As they were heading inside, Lauren slipped her hand over Simon Cowell's butt, according to a picture posted by Perez Hilton, via Ramey Pix.

The 13-week pregnant Lauren can't seem to keep her hands off of her baby daddy Simon, as a slew of PDA photos were snapped while they vacationed at the French Riviera, which included holding hands, kissing, and cuddling through the streets.

According to Entertainmentwise.com, Simon will introduce his pregnant girlfriend to his mother, Julie Brett, while they are back in London

"He is in the UK for a few days - he is going to oversee the launch of The X Factor," a friend told the Daily Star, Entertainmentwise.com reports. "Simon has also got some other business meeting to attend."

"But it's entirely plausible that he will want to pop and see his mum and take Lauren along," the source continued.

The website reports that Simon is back in the UK to unveil a mystery "fifth judge" on ITV's flagship talent search show, "The X Factor," tomorrow, August 30. This was teased on the official "X Factor" Twitter page earlier this week, Entertainmentwise.com reports.

Lauren and Simon were also spotted on a dinner date at an Italian restaurant called Scalini in Chelsea, where Lauren looked stunning in a pretty pink dress and white heels, showing off the beginnings of a baby bump.

Simon wore his trademark baggy button-up white shirt and jeans, but paired them with circular glasses.

An interesting thing to note is that Lauren also was carrying a magazine with Simon Cowell on the front cover, as they left the restaurant and smiled for the cameras, even sharing a kiss in the doorway.

These two lovebirds just can't keep their hands off each other!