At that same university, her future daughter-in-law Meghan Markle would graduate in 2003.
Diana and Meghan's Northwestern connection doesn't stop there however.
The Princess of Wales strolled along the campus grounds on June 4, the same day her granddaughter Lilibet was born 25 years later.
LA born Meghan completed a Bachelor's degree in theatre and international relations and told Marie Claire in 2013: "I had always been the theatre nerd at Northwestern University. I knew I wanted to do acting, but I hated the idea of being this cliché—a girl from L.A. who decides to be an actress.
"I wanted more than that, and I had always loved politics, so I ended up changing my major completely, and double-majoring in theatre and international relations."
WATCH BELOW: Meghan Markle talks about her university degree. Post continues after video...
Harry and Meghan chose to wait a few days to announce Lilli's arrival to the world and did so via a statement on Monday.
“It is with great joy that Prince Harry and Meghan, The Duke and Duchess of Sussex, welcome their daughter, Lilibet “Lili” Diana Mountbatten-Windsor, to the world. Lili was born on Friday, June 4 at 11:40 a.m. in the trusted care of the doctors and staff at Santa Barbara Cottage Hospital in Santa Barbara, CA," a spokesperson for the couple said.
"She weighed 7 lbs 11 oz. Both mother and child are healthy and well, and settling in at home."
Harry and Meghan also shared a personal message of thanks to their Archewell website, writing, “On June 4th, we were blessed with the arrival of our daughter, Lili. She is more than we could have ever imagined, and we remain grateful for the love and prayers we’ve felt from across the globe. Thank you for your continued kindness and support during this very special time for our family".