BUENA PARK, CA - AUGUST 22: Demi Lovato and Wilmer Valderrama celebrate Demi's 23rd birthday at Knott's Berry Farm on August 22, 2015 in Buena Park, California. (Photo by Jerod Harris/Getty Images)
BUENA PARK, CA - AUGUST 22: Demi Lovato and Wilmer Valderrama celebrate Demi's 23rd birthday at Knott's Berry Farm on August 22, 2015 in Buena Park, California. (Photo by Jerod Harris/Getty Images)