Bob Mackie is reflecting on his history-making partnership with Carol Burnett.

The designer behind the iconic costumes on The Carol Burnett Show, Mackie, 86, spoke with PEOPLE about the early days of working on the seminal variety series, which ran from 1967-1978.

Burnett, Mackie tells PEOPLE while aboard the Queen Mary 2 during Cunard’s 2025 Transatlantic Fashion Week, that the actress has always been “the most modest woman I’ve ever known.” He adds, “She would never be in a fitting with nothing on.”

Mackie, who is collaborating with Julien’s Auctions on the upcoming sale of pieces from his storied career, says that despite Burnett’s modesty, she trusted him enough to let him push boundaries if it helped heighten the comedy of her sketches.

“I used to do things with her as I’d read the script — ‘Oh, that’s not funny. What am I going to do to make this funny?’” he recalls.

Mackie also remembers one skit in which he suggested she wear a revealing costume to get some laughs. “The first show I have to fall out of a two-story window. It’s not really two stories. There’s mattresses under there. But it looks that way. So I better wear pants,” Mackie recalls Burnett telling him.

He had a different vision. “You can’t wear pants. That’s not funny. Nobody has funnier elbows or knees than you do,” Mackie told her. “I mean, you know what to do. You’re playing a woman who’s in trouble. Let’s do a shorter skirt — and tight, so it’s really awkward.”

Burnett quickly understood what he meant. “She went, ‘Ohhh.’ It all sank in for her all of a sudden,” he says.

Though she agreed to the skirt, Burnett still took steps to avoid showing too much skin. “I mean, believe me, she would have on thick underpants underneath,” Mackie says.

Collaborations on costumes and characters were common between Mackie and Burnett. “I loved doing it. And she loved the fact that I was doing that with her. But it didn’t occur to her to put those things in,” he says of the wardrobe element of a sketch. “If I explained to her what it was, she would go, ‘Oh. Oh, I get it now.’ It wouldn’t be in the script at all. ‘A woman walks into a bar,’ but then it wouldn’t give you any more information.”

In addition to creating one of the most famous moments in TV history with his iconic “curtain dress” for Burnett’s satirical take on Gone with the Wind’s Scarlett O’Hara, Mackie was also instrumental in shaping one of her most beloved characters: Mrs. Wiggins.

Wiggins, a ditzy secretary in a tight skirt, “was supposed to be 99 years old,” Mackie says — until he got involved.

“I called Carol, ‘You know, you’ve done this old lady,’” he says. “She would’ve done it,” Mackie adds, because Tim Conway, a main cast member on The Carol Burnett Show, wrote the sketch, but Mackie told her, “You’ve done this too often, let’s do something else.”

Never miss a story — sign up for PEOPLE’s free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer​​, from celebrity news to compelling human interest stories. 

Mackie continues, “I said, ‘Why don’t you be a secretary? Like those temps that come in every week — you have a different temp in the office and they don’t do anything except watch the clock and do their nails and have lunch.’”

That shift unlocked the character for Burnett. “She went, ‘Oh, now I know how to play that,’” he says. “And she did that. I did that with her over and over again on different things.”

Costumes worn by Burnett are among those on offer in Julien’s Auctions’ Bold Luxury: Bob Mackie, Stage Glamour &The Couture Edit. Online registration and bidding are now available. The live auction will take place on Wednesday, Dec. 3 at The Peninsula Beverly Hills at 10 a.m. PT.