For Christopher Lloyd, late wife Arleen Sorkin was more than his other half: She was his "center square."

The "Modern Family" co-creator and executive producer, who was married to Sorkin since 1995, paid tribute to his wife in an open letter published Saturday in Variety. Sorkin, best known for her role as Calliope Jones on "The Days of Our Lives" and as the original voice and inspiration behind DC Comics character Harley Quinn, died of multiple sclerosis at the age of 67, Lloyd's agent Christopher Silbermann confirmed to USA TODAY on Aug. 27.

Lloyd gushed about Sorkin's altruistic spirit, which he said was evident from the time they met working as staff writers on a sitcom.

"At lunch she approached me: 'My name is Arleen, and I'm an empath. I hear a clicking in your jaw that may be TMJ. Here is the number of a dentist who can help," Lloyd recalled. "I was equal parts enchanted and mystified. She'd already been the center square on 'The Hollywood Squares.' Why was she worrying about a stranger's TMJ? I came to learn that she worried about everyone."

Lloyd, who went on to have two children with Sorkin, praised his "big-hearted" wife for her compassion and generosity and reminisced on her most memorable acts of kindness: a fundraiser for a South African human and animal rights organization featuring a real-life orangutan, hiring an incarcerated former roller derby player as their children's nanny and fashioning a fake Emmy award for her dentist-turned-film-producer father.

"Credited as a co-producer, (Sorkin's father) was not entitled to a statuette, but she could not bear to tell him that. And he'd already planned a party to display his trophy," Lloyd wrote. "Thus began the odyssey of finding an old Emmy, polishing it up, getting his name engraved on it, all in time to ship it back East."

Though his wife's battle with multiple sclerosis took "much of her strength," Lloyd said Sorkin's "spirit never flagged."

"I don't know by what celestial accounting fate had decided to reserve the worst possible disease for one who, upon hearing that our boys' tap dance teacher had been shot, got him urgent medical care, away from danger, and a place to recuperate for two months," Lloyd wrote. "She loved people, believed in them."

He concluded: "I’m not sure Harley Quinn, the now world-famous character based upon Arleen and whose original voice she provided, wasn’t defined by that very quality, that achy loyalty, an unwillingness not to lead with her heart, come what may."

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Contributing: Naledi Ushe, USA TODAY