Ever the director, Steven Spielberg was already thinking about the next shoot at his portrait sitting with Marco Grob for this week's issue of TIME. Spielberg was curious about the photographer's plans to photograph Daniel Day Lewis, who plays the 16th president in the director's forthcoming Lincoln, later in the day. His schedule was free—so Spielberg offered to come back and help Grob with the shoot. "Spielberg is an icon, and to have him shoulder to shoulder with me as I shot was quite amazing," Grob says. "He ended up directing Daniel's gazes and poses, and talking to him during the shoot to create a really casual atmosphere." Spielberg limited his creative input to Lewis, though, even at Grob's insistence that he review shots, which ultimately suited the photographer's nerves just fine. "To have a very famous voice in your ear, at your shoulder, as you shoot could be quite stressful, to put it mildly," Grob says. "But this was obviously an incredibly fun and memorable experience."