How Did Radio Once Help Marlon Brando Act?

Famed actor Marlon Brando has died at age 80. Here's a little known fact according to allmovieportal.com:

[Brando] wore a small radio receiver to aid him remembering his lines in "The Island of Dr. Moreau"(1996). Co-star David Thewlis claimed he'd be in the middle of a scene and suddenly he'd be picking up police messages and Marlon would repeat, "There's a robbery at Woolworths".