Glenn O’Brien, the prolific New York-based fashion and culture writer as well as GQ magazine’s longtime “Style Guy,” has died at 70. He had been battling a serious illness for years, reports ArtNews.

O’Brien’s longtime friend, Jerry Salt, broke the news in a touching Facebook post Friday morning, and GQ also confirmed the news on Twitter.

We’re deeply saddened by the news of Glenn O’Brien’s passing. He was a legend, an artist, and the wittiest writer we knew.

— GQ Magazine (@GQMagazine) April 7, 2017

Throughout his decorated career in fashion journalism, O’Brien worked with such high-profile figures as Andy Warhol when he was the first editor of the artist’s Interview magazine from 1971-1974, as well as Jean-Michael Basquiat, who starred in a short film for which O’Brien wrote the screenplay.

O’Brien’s “Style Guy” column ran in GQ for 15 years, even becoming a book in 2000, until his contract was up in June 2015. Following his departure, O’Brien slammed GQ editors in an interview with Four Pins for the way the men’s style magazine had been handling its business matters.

In addition to his time as a columnist, O’Brien also wrote for Details, co-wrote Madonna’s Sex book and served as the creative director of Barneys New York. In November 2015, O’Brien joined Maxim as editor-at-large, replacing Kate Lanphear.

Recently, he had been hosting an interview show for WME/IMG’s M2M Apple TV network, titled “Tea at the Beatrice,” during which he chatted with style influencers including artist Richard Prince, director Baz Luhrmann and model Gisele Bundchen at New York’s Beatrice Inn.

This article originally appeared on The Hollywood Reporter.