Actor Mark Blum died on Thursday (March 26) at 69 years old due to complications from the novel coronavirus. In honor of her Desperately Seeking Susan co-star, Madonna took to Instagram to remember her old friend, and urge her followers to take the pandemic seriously."I Want to Acknowledge the Passing of a remarkable Human, fellow actor and friend Mark Blum, who succumbed to Coronavirus," she wrote alongside two stills from the 1985 film they starred in together.