Fortunately, the former star of The Facts of Life knew the perfect actress: her real-life 23-year-old daughter, Clancy Cauble.
Let's get this out of the way: they look alike. They sound alike. They even finish each other's sentences. "It just felt normal working with her," says Whelchel. "The chemistry is definitely there."
So what's the movie about?
"it's about a single mom blogger who writes about raising her teenage daughter," Whelchel tells PEOPLE. "There's a commenter who doesn't agree with her parenting. At the same time, she starts dating this wonderful pediatrician. Little does she know that the commenter is the pediatrician who she's having feelings for."
As two single women living together, do they ever give each other dating advice? "There's nothing off limits with us," says Cauble. "It's all out in the open. We do give each other opinions, but it always comes from a place of 'do you want to know my opinion?'
"I just don't think anyone is good enough for my mom," laughs Cauble. "Maybe George Clooney. Maybe. You really missed that one in the 80s, mom. I don't think that boat's gonna come back around."
But Whelchel admits that she sometimes holds her tongue. "You know, it's only backfired when I've given unsolicited advice," she laughs. "I think it's better to trust Clancy to make her own mistakes. She doesn't want to miss out on living life fully, and so much of that is making mistakes."
Learning From Each OtherBoth Whelchel and Cauble say there was a lot of learning on the set.
"My mom taught me the technical stuff," says Cauble. "This was my first feature length film. The director would give me a full paragraph of notes and I'd pretend I knew what he was talking about, but then I'd frantically grab my mom and say, 'please interpret and translate this!' It was really nice working with her."
But Whelchel learned from her daughter as well. "I feel very confident as a comedic actress, she says, "but I'm pretty insecure as a dramatic actress. Clancy could access the depth of emotion in real life. She could go to the deep places. That's very different from acting in an 80s sitcom!"
So with their first film behind them, do Whelchel and Cauble want to work together again?
Oh, absolutely," Whelchel says. "We'd love to do a sitcom together. We have a great idea for one, based on our lives. We're really going through the same things, just a generation apart. We both are new into dating. We're both trying to figure out what to do with our lives. There's a lot of inherent comedy in that. It would make a great show!"
Hearts of Spring premiers Saturday at 9 p.m. ET on the Hallmark Channel.