Kim Kardashian West admits she "never wanted to drink or party" after one night as Kourtney's "designated driver" at the University of Arizona.
The 40-year-old star has remembered going to see her older sister, now 42, at the University of Arizona and admitted it put her off a wild lifestyle.
She wrote on Instagram: "University of Arizona single handedly stopped me from turning into a wild party girl.
"I remember visiting Kourt on campus and being her designated driver.
"I hated all of the wild parties so much that I stayed home and never wanted to drink or party EVER…
"So thank you U of A. I was never a student there but u shaped my life more than you know (sic)"
Kourtney had transferred to the University of Arizona from Southern Methodist University in Dallas, and graduated in theatre arts and a minor in Spanish.
However, on 'Keepung Up With The Kardashians' three years ago, Kim admitted she had a "wild phase" and said she took ecstacy when she married producer Damon Thomas in 2000, and when she made her sex tape with Ray J three years later.
She added at the time: "Like, everything bad would happen... I definitely went through a wild phase, I would say in my late teens.
"I'm not like that anymore. But I still have fun — don't get it twisted, I'm always the life of the party."
And an insider revealed shortly after that Kim "definitely does not do drugs and hasn't for years — and even then she barely dabbled".
They explained: "Now she drinks here and there, but mostly abstains. She may have a glass of champagne on a holiday or for someone's birthday, but it's rare."
And another source added: "[She] pretty much doesn't drink at all. She's not a partier and it's just not part of her life.
"Occasionally she'll have a drink, but she really doesn't like the taste of alcohol."