In the 2019 Judy film, at which point does Margaret Hamilton appear?

From what I understand, Margaret Hamilton makes an appearance in the movie but I could never figure out when. Keep in mind, I obviously don't mean the real Margaret Hamilton since she died years yang lalu but apparently actress Fenella Woolgar played her in the movie somewhere. Was she the one who was riding that bike during the very beginning of the movie when Louis B Mayer was talking to Judy?