Weiss: Diana Ross’s 75th birthday; parties for Beyoncé; and one of my most exciting is working for Oprah. I was a huge fan, so you can imagine that when we met, it was quite overwhelming for me.

Since planning the Kardashian matriarch’s celebration in 2015, Weiss has worked with the family on events like Kylie Jenner ‘s daughter Stormi Webster‘s first birthday, Kylie’s 21st ...