How Kelsey Grammer and Daughter Spencer's Christmas Movie Helped Heal Their Strained Relationship

Celeste Sloman/Lifetime

Kelsey Grammer is the first to admit that his relationship with his oldest child, star of Greek and the Rick & Morty voice actress Spencer Grammer, has been strained at times over the years — especially after he split from her mom, actress Doreen Alderman, when she was a toddler.

Now, they're starring together in a Lifetime holiday movie, 12 Days of Christmas Eve, as a father and daughter with a strained relationship.

"I certainly regret I let her down a couple of times," Kelsey, 67, tells PEOPLE of how work took him away from his young family after he was cast on Cheers in 1984. He notes that the role and the sudden 20-hour workdays changed everything at the time. "Obviously she was a child of divorce," he says of Spencer. "It was hard on us."

He adds, "I feel sorry about it, but I'm also thankful that we had a chance to make amends."

Amends they have certainly since made — though the road wasn't always easy.

Lifetime

When Kelsey, who has six younger children, was pitching The 12 Days of Christmas Eve, which is a tale about a self-centered and workaholic father who puts his business above being there for his family, he realized Spencer would be the perfect person to play his onscreen daughter.

"It seemed like the right idea to me," he says of wanting to cast her in the role of the hard-working surgeon and single mom who is endlessly disappointed by her dad not being there for her. However, he hadn't actually asked Spencer if she was interested yet. "I said, we'll have to make sure she wants to, because you never know," Kelsey says. "We blow hot and cold like all fathers and daughters do."

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Spencer, 39, who has been getting her graduate degree in directing from Columbia University in New York City for the past five years, says she didn't immediately say yes. But after talking with her dad more and figuring out scheduling, she realized how fun it could be for both of them to work together onscreen for the very first time. It didn't hurt that the plot seemed very familiar to their real-life relationship.

"There's definitely aspects of this movie that resonate with me personally," Spencer says. "First of all, playing daughter to your actual father is something unique. He's been such an incredible influence on my craft and my performances and also my work ethic, so working with him was actually quite a pleasure."

Celeste Sloman/Lifetime

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But it was the message that resonated with them both: At the end of the day, being selfless and putting those you love above work and money is the true meaning of Christmas. And really, the meaning of life.

Spencer adds that the experience wasn't just fun, but also a bonding experience.

"In The 12 days of Christmas Eve, this father and daughter get to repair their relationship at some point. And the dad comes back to really, really figure out what the meaning of Christmas truly is. And honestly for me, for that month that we shot, it was incredibly fun and wonderful to spend time with my dad," she says. "I think it was really healing for us."

She adds with a laugh, "So thank you Lifetime, for the therapy!"

It was so much fun that the two are already talking about doing a sequel that focuses on Spencer's character going through something similar to what her father does in this film: neglecting family when work dominates all of her time and energy.

Read more about Kelsey and Spencer Grammer in this week's issue of PEOPLE, on stands now. 

For his part, Kelsey says he'd absolutely love to work with his daughter again. "She's terrific in the film," he says. "She's a very talented woman and I'm very proud of her. I even got to say that on camera a couple of times, along with a few things I never got to tell her. So it all turned out really well."

He adds that the message of the film is also about how one can be reborn. "It's about the prophet of love, and how that can remake a man," he says. "A man who finds love it born again. Which is a wonderful gift, and one we can have every Christmas."

12 Days of Christmas Eve premieres Saturday, Nov. 26 at 8 p.m. ET on Lifetime.