John & Jen's Romantic Weekend

While TomKat was busy throwing their mammoth housewarming bash at their Beverly Hills home, a more intimate party was taking place just down the street at the Beverly Hills Hotel, as John Mayer and Jennifer Aniston shared a romantic dinner at the hotel's posh Polo Lounge on Saturday night.

An eyewitness tells OK! the two looked "very much in love" and "only had eyes for each other."

Around 11 p.m. on Saturday, the pair left the Polo Lounge and disappeared into the hotel somewhere, prompting whispers that they'd gotten a room for the night. However, a couple hours later they finally exited the hotel for good, as John drove Jen in her Porsche SUV to her home in the hills of West Hollywood.

"Jen is so cautious about the men she sees," one insider tells OK!. "John may be a keeper for a while."According to the source, the actress "likes guys who are light-hearted and funny," which appears to fit John to a tee.

And it looks like things might be getting even more serious as Jen took her troubadour boy-toy to meet her closest friends, Courteney Cox and David Arquette. The foursome enjoyed a quiet night in on Sunday at the Cox-Arquette's beachside home in Malibu.