Leachman died on Wednesday at the age of 94.
Cloris Leachman was a force to be reckoned with in Hollywood. The beloved actress, who died Wednesday at the age of 94, portrayed Phyllis Lindstorm, Mary's landlady, on The Mary Tyler Moore Show in the '70s.
Ed Asner, who played Mary's boss, Lou Grant, had a close friendship with Leachman on and off screen, telling ET's Nischelle Turner she was "always an energy source."
"A bit charged up. She was a honey. The kind woman she was," Asner, 91, recalled of his dear friend. "But we got awful chummy, and we dug each other a lot. When we first started the show, she got me to not worry about reading the teleprompter, rewind the script, improv… We did it with improv and it worked well."
Leachman had more Emmy nominations than any other actress, winning a total of eight primetime awards. She tied with Julia Louis-Dreyfus for the most Emmys ever. She was also an Oscar winner for the 1971 drama The Last Picture Show.
As for what made her a terrific comedian and dramatic star, Asner said, "She used what was there. She didn't cry about it. She had pride in herself and she did not like being bound down to any rules and regulations."
"She was a free cat. She was just marvelous, a marvelous actress," he continued. "And she would come up with some wonderful ideas."
Working with Leachman was a wonderful time for the actor, who, when asked what would surprise fans to know about the late actress, replied, "The fact that she could be serious about anything would surprise her fans."
"I'll carry my memories to my grave," Asner shared. "I loved her. She was a sweet mama."
The famed actress' rep confirmed to ET on Wednesday that Leachman died in her sleep of natural causes at her Encinitas, California, home. Her daughter, Dinah Englund, was by her side.
As news broke of her death, some of the acclaimed performer's famous friends, fans and former co-stars paid tribute to her memory. Asner also posted a photo of the two together, along with some sweet words.
Mel Brooks -- who directed Leachman in some of her most iconic roles in Young Frankenstein, High Anxiety and History of the World: Part 1 -- honored the actress' memory with a heartfelt message of love and respect.
"Such sad news -- Cloris was insanely talented. She could make you laugh or cry at the drop of a hat," Brooks shared. "Always such a pleasure to have on set. Every time I hear a horse whinny I will forever think of Cloris’ unforgettable Frau Blücher. She is irreplaceable, and will be greatly missed."
For more on Leachman's legacy, watch below.
EXCLUSIVE: 'Mary Tyler Moore Show' Stars Ed Asner and Cloris Leachman Remember Their Leading Lady