The secret's out!

Katharine McPhee and David Foster had a dinner date at Craig's last night, just one day after we spotted them kissing and outed them as a couple. Although their camps initially denied the romance, they're now slowing going public with their relationship.

"It’s a little more than casual, but they’re not exclusive. Kat thinks they should be a little more serious, but it’s mainly casual on his part. She’s gone out to dinner with his daughters Erin and Sara. Kat was with them at David’s charity event [in Vancouver on Saturday, October 21]," a source dished to Us Weekly.

It sounds like she's already won over his family, too!

"David Foster and Katharine are hooking up and casually dating on the down low. They are just having fun right now, but they have such a great chemistry and really connect organically on so many levels. There is potential for things to escalate in the future. They were working together and things blossomed as they worked closer with one another. Erin and Sara are particularly fond of Katharine are particularly fond of Katharine and think she is just the most wonderful person. They are totally team McFoster!” the source added.

Things have been going on for longer than anybody thinks, as the two first started seeing each other seeing other in the spring, but cooled off as he courted other beauties like Christie Brinkley and Elizabeth Hurley.

"They started hooking up in March or April. They called things off for a little bit, but are now back together," the insider revealed.

We wonder what Yolanda Hadid thinks of her ex-husband's new lady love?