It was pretty obvious from the trailers and a series of photos that actress Renee Zellweger has nailed the look of Judy Garland, effectively transforming herself physically into the Wizard of Oz actress. But in the new featurette released on the film, cast and crew explain how, vocally, she was able to capture the iconic sound of the late singer as well. With all of this in mind, and watching the above footage, it truly is amazing that she has been able to do so.

Judy reaches theaters on September 27.