By Rachel DeSantis
January 26, 2017 at 05:57 PM EST
CBS via Getty Images

Valerie Harper posted a touching tribute to the late Mary Tyler Moore, her former Mary Tyler Moore Show co-star who died Wednesday at age 80.

“To the world I’ll miss you ‘Mair,'” Harper shared on Twitter. “I will always be your co-pilot. I will always love you, darling Mary Tyler Moore.”

Harper and Moore starred for several seasons together on The Mary Tyler Moore Show as best friends and neighbors Mary and Rhoda. The former costars last appeared together on screen in 2013 on an episode of Hot in Cleveland that also featured Mary Tyler Moore alum Cloris Leachman, Georgia Engel, and Betty White. The episode would be Moore’s final television appearance.

Following the 2015 debut of PBS’ documentary Mary Tyler Moore: A Celebration, Harper spoke to EW in praise of her longtime friend.

“I met her on television!” she said of her first encounter with Moore. “I was watching her like the rest of the world on the Dick Van Dyke Show…she was adorable. She was so cute in those tight little pants, and classy — a very classy lady. And a brunette! I loved that! I used to come home from high school and watch the show, and then when they called me and said we think you might be good as her friend Rhoda, I was like, well that sounds very good… She’s an incredibly generous girl. She’s really just a great person.”

See more reactions from the stars here.