After sustaining serious injuries while shooting the upcoming third installment in the Maze Runner franchise in March, the 24-year-old Teen Wolf star resurfaced on Sunday in a fan's Twitter photo, showing off an impressively gruff full beard.
"MY LIFE HAS BEEN MADE, meeting you was the best thing ever," the fan captioned the pic.
Meanwhile, production on Maze Runner: The Death Cure has halted while O'Brien recovers from his injuries. The actor was hospitalized in March after reportedly being run over by a car involved in a scene on location in Vancouver, Canada.
During Teen Wolf's Comic-Con panel in July -- after announcing that the MTV show's sixth season will be its last -- creator Jeff Davis gave an update on O'Brien, saying he was "still at home, recuperating" after the scary incident.
And O'Brien's Teen Wolf co-star, Shelley Hennig, told ET at Comic-Con, "He's doing well, and he wants everybody to know."