Valerie Harper Remembers ‘Sister and Soulmate’ Mary Tyler Moore as ‘One Hell of a Girlfriend

Valerie Harper is mourning the loss of Mary Tyler Moore: a longtime friend and costar who she also considered a “sister and soulmate.”

On Wednesday, the world said goodbye to The Mary Tyler Moore Show star when she passed away at the age of 80.

In an exclusive statement to PEOPLE, 77-year-old Harper remembers her costar, with whom she acted from 1970—77.

“Last week, to prepare me, I was kindly warned by Mary Tyler Moore’s dear husband, Dr. Robert Levine, that she was in the very last stages of life,” Harper, who played Moore’s best friend and upstairs neighbor Rhoda Morgenstern on the comedic series, told PEOPLE. “But still I cannot stop the emotions I’m experiencing, since she was my acting colleague, my sister/soulmate, and above all, ONE HELL OF A GIRLFRIEND!”

She continued, “Working together we knew each other so well we could anticipate each other’s moods, ever ready to engage and KNOW there would be an appropriate response from Mary.”

“I will always feel privileged and honored with the amount of quality time I was able to spend with Mary,” she said, adding, “I’ll miss you ‘Mair.’ I will always be your co-pilot. I will always love you, darling Mary Tyler Moore.”

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Harper also took to Twitter to pay tribute to her late costar: “To the world I’ll miss you ‘Mair.’ I will always be your co-pilot. I will always love you, darling Mary Tyler Moore.”