John Mayer and Jennifer Aniston double-date for steak

John Mayer and Jennifer Aniston must be getting serious.

Thursday night they went on a double date. To a steak house!

OK, the other couple was Courteney Cox and David Arquette and the steak house was the ultra-hip L.A. beeferie STK.

Click here for photos. Jen looks really happy. It's about time. We're happy for her.

And it is perhaps a measure of just how comfortable Jen is with John that she brought him to the steakhouse bash, sponsored by Kitson and honoring Jeffrey Sachs (an old pal of Brad Pitt) for OmniPeace, founded by Mary Fanaro.

Photo: John Mayer and Jennifer Aniston's first public outing last month in Miami at the wrap party for her new film, "Marley & Me."
WireImage