John Mayer may have dumped her after a few weeks of dating/hooking up, but Katy Perry is determined to perk up! After hitting the bars in Hollywood, the 27-year-old pop singer took a trip to Disneyland on Saturday.

"Today I am promised happiness," she tweeted. "Let's do this!" Katy later posted a photo from dinner and added, "Why, yes! WE will dine with you, Walt!"

Mayer reportedly told the newly-divorced Perry that he had changed his womanizing ways, but shortly after the two began their romance he dumped her. "John did a real number on Katy," a source told Radar. "She held off from his advances for the longest time, but he laid on the charm thick and promised her he was a changed man. She eventually gave in, fell head over heels for him and then - yep - once he had made his conquest, he dumped her."

Mayer was spotted out over the weekend with noticeably shorter hair, so it certainly seems like the 34-year-old singer wants all the single ladies to know that he's back open for business. While it's a step in the right direction, we have to wonder what kind of a girl would be silly enough to fall for the serial heartbreaker!