Katy Perry and John Mayer had a Valentine's Day date night yesterday at the Vincenti restaurant in LA. The sweet outing together comes after a big week for the pair. Over the weekend, Katy and John showed PDA on Saturday at Clive Davis's annual pre-Grammys party, and then went on to show even more affection at Sunday's Grammys. Katy Perry's Gucci Grammys dress was one of the most talked about outfits at the show; her good friend Ellen DeGeneres was seen admiring the gown with her mouth hanging open. Now, though, Katy and John are having some downtime. On Twitter, Katy sent well wishes to her followers. Instead of wishing them a happy Valentine's, she wrote, "Happy Thursday everyone!"