The Balmain creative director recently collaborated with the lip kit guru on a capsule cosmetics collection and named the Keeping Up With the Kardashians star artistic director of make-up for his spring 2020 show - which she ultimately missed due to illness - and he has praised his pal as a "strong" and confident woman who wants her friends to "feel good".
He said: "She's such a strong woman and I love the way that she's so confident and always making sure that her friends are feeling good. And she's so generous.
"When you do have problems, she will always be there for you. It's a beautiful relationship."