Willis also wrote songs for artists including Debby Boone, Rita Coolidge, Crystal Gayle, Sister Sledge, Jennifer Holliday, Gladys Knight and the Pips, Cyndi Lauper, Crystal Waters, and Taylor Dayne. Songs she co-composed for other artists that became hits include "Lead Me On" by Maxine Nightingale, "Neutron Dance" by the Pointer Sisters, "What Have I Done to Deserve This?" by Pet Shop Boys featuring Dusty Springfield, and "I'll Be There for You" by The Rembrandts. "I'll Be There for You" was used as the theme song of the sitcom "Friends" and went on to become one of the biggest television theme songs yet. Willis jokingly referred to this song as "the whitest song I ever wrote". In 1995 Willis was Emmy-nominated for "I'll Be There for You".