Duke and Baxter will play a longtime couple who meets Blaine at a jewelry store and offers to be his mentor.
Patty Duke and Meredith Baxter will join the "Glee" family. The Helen Keller of "The Miracle Worker" and the newly-out lesbian Baxter of "Family Ties" will appear on the FOX series for the season finale that will start shooting next week.
They will be guesting as a lesbian couple who has been together for 25 years. They will run into Blaine (Darren Criss) at a jewelry store when the high schooler wants to buy a ring to [SPOILER ALERT!] propose to his on-off boyfriend Kurt (Chris Colfer).
Duke, 66, will portray the jewelry salesperson. The Oscar-winning actress' character and her longtime partner played by 65-year-old Baxter will offer to be Blaine's mentor.
Described as "topical and sweet," the upcoming outing, according to a source from E! News, takes inspiration from the recent Supreme Court case regarding same-sex marriages.