DEMI LOVATO'S ROMANCE AND KNOTT'S BERRY FARM

Demi Lovato Let the birthday celebrations continue! Demi Lovato may have received an adorable puppy Thursday when she turned 23. But the "Cool for the Summer" singer managed to keep the party going as she traveled to Knott's Berry Farm Saturday for an afternoon with boyfriend Wilmer Valderrama. The Hollywood pair arrived at the Buena Park, Calif., theme park with friends where they immediately headed for the roller coasters including Silver Bullet and Xcelerator. According to attendees, the couple was always holding hands even as they screamed together on the thrill rides. "They made a lovely couple," an eyewitness told E! News exclusively . "They indeed looked very happy." Another eyewitness spotted the pair "hugging" and "making out" after enjoying dinner together at one of the park's restaurants.