A source told PEOPLE that Fallon's mother is sick, and the comedian went to the hospital to be by her side.
Viewers spotted both his parents ― who grew up together in Brooklyn ― seated in the audience when Fallon took over "Tonight Show" hosting duties from Jay Leno in 2014. Fallon recently tweeted that he and his mother had spoken on the phone three times in one day, only to have Gloria say, "We don't talk enough".
"She wasn't allowed to leave her stoop in Brooklyn", the former "Saturday Night Live" star once told NY magazine.
"She was a nun for about a month, but then she was like, 'You know what?" I think there was like a thing where everyone wanted to be a nun.' Our hearts and thoughts go Gloria's family and friends. We would not be surprised if Fallon offers up a tribute of his own to his mother when he does return to the show.
Fallon, 43, has often talked about his childhood and family.
Earlier this year, Fallon donated $100,000 to Saugerties High School to support technology in the arts.