Scarlet Johansson is hoping to hide certain details of her past from her kids.

During an appearance on "The Drew Barrymore Show" Wednesday, the 37-year-old actress revealed the one thing she hopes her children will never know about her.

"My daughter may have asked me this before. I used to smoke when I was younger and I'm so ashamed. I just don't want her to ever think that I ever thought it was cool 'cause she can never, ever, ever smoke," the "Sing" star — who is mom to 7-year-old daughter Rose Dorothy and 7-month-old son Cosmo — admitted.

"'Cause, that's what you do. You forbid your kids from doing things and then they don't do them. So yeah, I just hope she never figures that out," she quipped.

But, it looks like the "Black Widow" star might have a hard time keeping her smoking habits from the past a secret from her daughter because Rose is currently at an age where she is curious about everything, the actor recently told InStyle.

"Why are you tweezing your eyebrows? Why are you curling your lashes? What's a tampon? What's it for?" said Johansson, imitating her daughter.

Scarlett Johansson
Scarlett Johansson is pictured attending the 92nd Annual Academy Awards on Feb. 09, 2020 in Hollywood, California. Steve Granitz/WireImage

"She asked me why my underwear went up my butt crack, and I had to try to explain what a panty line was. I was like, 'cause you don't want a line in your pants,' and she was like 'Why?' And I was like, ''cause then you could see my underwear,' and she was like 'But you are wearing underwear.' Like I know, it's weird," recalled the mom of two.

While the little one is curious about a lot of things, the one thing she doesn't really show much interest in is her baby brother, Johansson shared.

"She has a lot going on in her life. She's got a very active social calendar, so she's not as interested in the baby as, I don't know, let's say, like, any other thing really?" the star said in a virtual interview with Jimmy Fallon on an episode of "The Tonight Show."

Johansson also revealed that there is something she does that her daughter finds "a little" embarrassing nowadays. "I do a little dance when the school bus pulls up, and she doesn't like that. Of course, then I exaggerate it even further," Johansson confessed to Fallon at the time.