EXCLUSIVE: David Singh, who has worked in creative advertising at both Disney and most recently at Sony Pictures Entertainment, is going to 20th Century Fox after leaving Sony two weeks ago. He is expected to be named exec vp of creative advertising working under Marc Weinstock, head of domestic marketing. He had served at Sony for three years working on a number of campaigns and left on his own volition. He previously worked at Disney for 10 years.  Singh will work alongside Arnaldo D’Alfonso, executive vice president and creative director. Weinstock and Singh worked together at Sony and D’Alfonso and Singh worked together previously at Disney. They will be co-running the creative advertising department.