"Awful day at shoot...acted badly...did awful action...and gave suggestions without understanding them myself. Delayed the shoot," Shah Rukh posted on social networking site Twitter.
"Everybody believes tomorrow will be better... I hope everybody is right. I think I should just forget it...move on..shower...feed my face, watch a film...," he added.
"Ra.One", about a superhero who can freeze electricity, is one of Shah Rukh's most ambitious projects.