Related Clues:

• "Cast of thousands" member
• Expansion
• Newsdealer's shout of old
• Unrequired
• Tribe member in many films
• Hollywood walk-on
• Garage, perhaps
• Run over
• Building wing, e.g.
• Extra, and this puzzle's title
• Old newsboy's call
• One without lines, generally
• Hollywood "spear carrier"
• Crowd scene constituent
• When repeated, start of an old shout that ends with the starts of 17-, 26-, 47- and 61-Across