Music fans were blown away when this iconic ’70s pop hit made an appearance in the 1980 coming-of-age film starring Kristy McNichol and Tatum O’Neal, introducing the song to a new generation of fans.

Before teen idols were carefully polished for magazine covers and filtered for Instagram, there was Kristy McNichol. She didn’t just act like a teenager—she was one. And more than that, she felt like ...