When Mark Hamill wore the stormtrooper suit on the Death Star, he actually couldn’t see anything.
This improvised, and may I say genius, move by Mark Hamill to include his phone number on film forever wasn’t the only time he improvised a line on set.
So he said his famous line “I can’t see a thing in this helmet” to Harrison Ford when he thought they weren’t filming.
George Lucas liked it and decided to let him keep saying it in additional takes.