LITTLE HOUSE ON THE PRAIRIE -- Season 1 -- Pictured: (l-r) Melissa Gilbert as Laura Ingalls Wilder, Michael Landon as Charles Philip Ingalls  (Photo by NBCU Photo Bank/NBCUniversal via Getty Images via Getty Images)
CNN  — 

“Little House on the Prairie” star Melissa Gilbert is remembering her late co-star Michael Landon, more than three decades after he died of pancreatic cancer at age 54.

“Today is the 31st anniversary of the death of one of the most influential people in my life and I am so, so sad,” Gilbert wrote in an essay for PanCAN, a charity that funds those affected by the disease.

She continued: “You would think that I would have been feeling this kind of sadness last year, on the 30th anniversary. After all, 30 seems like more of a landmark number than 31. Yet here I am, feeling the grief and loss deeply today. Grief and loss don’t care about landmark numbers. In my experience they creep up and hit you when you least expect it.”

Gilbert added she is missing Landon now more than ever.

“Like today,” she wrote. “Today I am missing my mentor, my acting partner, my favorite director, father figure, friend, and boss. Today I am missing my Pa. Today I am missing Michael Landon. So much so, I can feel it in my chest, in my heart. I am aching for him.”

“Little House on the Prairie” aired from 1974 to 1983. It followed the Ingalls family in Plum Creek, Minnesota. Gilbert played the second-oldest daughter Laura, who narrated the show.

Gilbert also asked for help in finding a cure for pancreatic cancer.

“On this anniversary of the death of my Pa, Michael Landon, to please make a contribution to PanCAN. Do it in Mike’s name. You can help end this disease and it’s horrid, indiscriminate destruction today. Please, please help in whatever way you can,” she wrote.