Actress Joey King reprises both her role as Elle Evans and her wig for The Kissing Booth 3, the sequel to The Kissing Booth 2, which also finds King in a wig. With exception to one scene, King doesn't show her real hair for the entirety of the final film of The Kissing Booth trilogy, which seems slightly odd and unnecessary until one understands the context.
Though predominantly filmed in South Africa, The Kissing Booth trilogy follows California teen Elle and her time during and after high school in Los Angeles with her best friend Lee Flynn (Joel Courtney) and Lee's brother, Noah Flynn (Jacob Elordi), who is Elle's boyfriend. After The Kissing Booth 2's cliffhanger ending, The Kissing Booth 3 opens with Elle struggling to choose between going to college at Berkeley with Lee or at Harvard with Noah. While churning over her collegiate options, Elle, Lee, Noah, and friends spend one last summer together at Lee and Noah's soon-to-be-sold beach house.
One of the reasons why Elle can't seem to fully let her hair down in The Kissing Booth 3 is because it's not the actress' real hair. As it turns out, King previously shaved her head in 2017 to star as Gypsy Blanchard in Hulu's true crime series The Act. That series, based on the real-life story of Gypsy Rose Blanchard, whose mother suffered from Munchausen syndrome by proxy and made her daughter sick, required King to go bald due to Gypsy believing she had cancer. Seeing as how The Kissing Booth 2 and The Kissing Booth 3 were filmed back-to-back only months after The Act finished production, King's real hair hadn't yet grown back, meaning King had to wear a wig to play long-haired Elle in both movies.
However, King reveals her real hair in one scene toward the end of The Kissing Booth 3. After the story jumps forward six years into the future, Elle appears post-college in her mid-20s with a short pixie cut. At an impromptu reunion for Elle, Noah, Lee, and Lee's girlfriend Rachel (Meganne Young), only Elle stands out as a character who has truly changed over the course of six years, thanks in large part to the producers' decision to use King's real hair here.
Fortunately, despite all the partying and summer shenanigans Elle, Lee, and Noah get into for the trilogy finale, Elle doesn't have any obvious wig slip-ups throughout both The Kissing Booth 2 and The Kissing Booth 3, even in comparison to her natural long hair of the first film. In July of 2020, King posted an Instagram video revealing her makeup, wardrobe, and wig transformation to play the role of Elle, showing an acute before-and-after of King's hairstyles. With another Instagram image showing King in costume for the upcoming Bullet Train movie, fans can catch a glimpse of a much darker, moodier King than the bright-eyed girl of Kissing Booth fame.