McNichol, 49, who has lived with her partner Martie Allen, also 49, for the past two decades, decided to make a statement about her sexuality and share this photo because she is "approaching 50" and wants to "be open about who I am."
She "is very sad about kids being bullied," her publicist Jeff Ballard tells PEOPLE. "She hopes that coming out can help kids who need support. She would like to help others who feel different."
Best known for her Emmy Award-winning role as Buddy Lawrence in the '70s show Family and later as Barbara Weston in Empty Nest, McNichol left it all behind when she dropped out of Hollywood to focus on her health.
Done with acting, McNichol spends her time focusing on tennis, yoga, travel and raising her beloved miniature dachshunds. "She is very happy and healthy," says Ballard. "And she enjoys living a very private life."