The ‘I Love Lucy’ stars penned passionate letters to one another in the early 1940s.

Lucie Arnaz revealed she was stunned by some of the love letters her parents, Lucille Ball and Desi Arnaz, penned to each other in the early days of their relationship.

In an interview with Palm Springs Life, Arnaz, 74, opened up about the newly published book, Lucy & Desi: The Love Letters, a compilation of personal letters between the beloved I Love Lucy stars dating back to the 1940s when they first fell in love.

“Well, when I first read them, they were surprising to me — the depth of the passion … the jealousies, the childishness. They’re so naïve, and young, and silly,” Arnaz revealed of the love letters.

“When I first read them, I was kind of shocked,” she admitted. “Those were not the people that even I knew, and of course, they wouldn’t be. It was in the ’40s. I wasn’t born until 1951. They weren’t those people when I was around. They were never those people again.”

“Really, this is what’s left of their real marriage at the best of times,” she added.

Ball married the Cuban bandleader in 1940 and divorced him in 1960, at the tail end of their I Love Lucy fame. Their love story was tumultuous, in part due to Desi’s alleged indiscretions.

In a book excerpt shared by People magazine, Ball, then 29, issued a passionate plea to her “baby.” “I think of you instantly upon waking — all day — all nite — until I go to sleep again,” she wrote to Desi, before begging him to stay away from the “awful dames” she disliked so much. “Please don’t prefer them instead of me — really darling it won’t be worth it., she added in the letter dated October 27, 1940, which was  just one month before the two married.

After Lucille Ball and Desi Arnaz died in the late 1980s, their children Lucie and Desi Jr. were left with a massive amount of history to go through.

“It was overwhelming on so many levels,” Arnaz told The Desert Sun in an interview. “We ended up creating two museums with … stuff. It was like the loaves and the fishes.”

One of the things she kept was her parents’ love letters, which were secured in a lockbox and wrapped with ribbons in two stacks.  Arnaz marveled over the fact that her mother kept all of the letters despite the fact that her parents both were married to other people— Ball to comedian Gary Morton in 1961 and Desi to Edith Mack in 1963—after their divorce.

“It wasn’t unusual that there were letters that they wrote to each other, but that she kept both of them,” Arnaz told People. “That’s what’s so incredible to me…. And they were so beautifully kept.”