OLDHAM, England — In an exposition hall eight miles outside Manchester, on a softly humming treadmill stripped of its handrails, the best darts player in the world was trying to keep his balance and his cool.

A film crew from Sky Sports had joined Michael van Gerwen in Oldham on Friday to have him pantomime and pose in front of a green screen for a series of television spots. They would digitally alter the video to make it look as though van Gerwen were strolling through the streets of London, where the World Darts Championship are set to begin on Thursday night.

Van Gerwen, for the most part, was an agreeable participant, following their various commands — “O.K., Michael, do the thing again where you move your neck” — even though the treadmill kept jamming, and he kept stumbling off, which made him laugh nervously. At one point, the power in the room cut out, shrouding the entire group in darkness. Van Gerwen stepped aside, opened a diet soda and ruminated on the odd scene.