As Katie Miller Douglas, Tina Cole became the first female regular on the long-running family sitcom My Three Sons. “I had to be sweet, but not syrupy; I had to be feisty, but not bitchy,” Tina tells Closer. She also had to overcome an obstacle she wasn’t even aware of. “I found out later that Don Grady [who played her husband] fought my casting. He didn’t think I was right for Robbie!”

From 1960 to 1972, My Three Sons, the story of a widower, played by Fred MacMurray, raising his family with the help of a curmudgeonly in-law entertained and delighted viewers of all ages. Tina, 80, guest-starred on two early episodes, but started playing Katie in the show’s eighth season when Robbie decided to propose to his girlfriend.

It’s ironic that Tina, who had previously starred on Hawaiian Eye, and Don didn’t have better chemistry from the start. “The kissing was pretty awkward. The director called ‘cut’ and said he needed us to pretend we liked each other,” recalls Tina, who was sent to a corner to “practice” kissing with Don until they got it right!

Tina didn’t need to work nearly as hard to win over series star Fred MacMurray. She had met the veteran actor and his wife, June, during her audition and hit it off immediately. “I got a huge bouquet of flowers my first day of work. People were kind of shocked because Fred was known for his frugality,” says Tina. A man of few words in his private life, Fred came alive for the camera. “He was so funny,” says Tina. “He could say more with one raised eyebrow than most actors could say with their whole bodies. He was just a master to watch and learn from.”

Don also warmed up to Tina in a very big way — around three years into her run on the show, the costars started dating! “We were just crazy about each other,” confides Tina, who explains that they didn’t wed because they were never in the same place at the same time. “He asked me to marry him and I wasn’t ready,” says Tina, who gave their romance a second try a few years later. “That time, I wanted to marry him and he wasn’t ready. So, it was unrequited.”

In 1972, Tina and the rest of the cast were “shocked” and “devastated” when the network canceled My Three Sons after 12 seasons. Yet the show has continued to live on — and win over new fans — in syndication and streaming platforms. “It has not been off the air since 1972,” Tina says. “I still hear from people who wanted to be part of our family. They liked that the dad was gentle and wise. They like the closeness. Even though it didn’t start out as a nuclear family, it became one, and I think people really miss that.”