Katy Perry and John Mayer went on a romantic dinner date at the Sunset Tower hotel on Valentine's Day, and after that the couple headed to Bootsy Bellows in West Hollywood to party it up with their pals.

But what's that sparkly ring Katy was flashing on her left hand? She wasn't wearing it last week, but we have a feeling if she actually got engaged, someone would have leaked the news by now, right?

Earlier on Friday we caught John picking up a last minute V Day gift for his sweetie ... wonder what's in the red bag!?