Kourtney Kardashian talks beauty, style ... and undergarments

Mom knows best!

Kourtney Kardashian says the best piece of advice that her mom, Kris Jenner, ever gave her and her sisters was to “never leave home without a perfect bra and underwear set because you never know who might see it.”

Ooh la la!

The 34-year-old reality starlet shared that juicy tidbit and others at an intimate breakfast last week celebrating the launch of the new Kardashian Beauty Holiday collection, which was held at Locanda Verde in TriBeCa.

The line, formerly known as Khroma, features old favorites like Kardazzle face palettes and Kardashian’s everyday must-have obsession — the bronzer — along with fun new products like the Touch Tone gradient eye shadow palettes and the lip-plumping shimmering lip glosses. All products are $12.99 or less and are available at CVS.

The mama of two and healthy-thinking gal says the ingredients are the most important part to her when it comes to Kardashian Beauty: Products are free of parabens, petro-chemicals, sulfates, GMOs and synthetic fragrance. 

The self-proclaimed glamour girl confesses to needing to curl her lashes to wake up her eyes, and says the people closest to her often share their opinions about her style.

She says boyfriend Scott Disick recently nixed her bright lip color before a date night, and that her sisters – unsurprisingly – always let their opinions be known.

“My sisters always point out if something is off,” she says. “They are the harshest critics.”