It's unknown if Sheeran will be able to join host Kieran Culkin on Saturday Night Live in 13 days -- the singer-songwriter says he's self-isolating and dropping any in-person commitments. "Hey guys,Quick note to tell you that I’ve sadly tested positive for Covid, so I’m now self-isolating and following government guidelines," Sheeran wrote on Instagram. "It means that I’m now unable to plough ahead with any in person commitments for now, so I’ll be doing as many of my planned interviews/performances I can from my house. Apologies to anyone I’ve let down. Be safe everyone x."