Brady was the mystery guest at Thursday's "Saving by Shaving" annual fundraiser for the Dana-Farber Cancer Institute in Boston.
Brady showed off his new look on Instagram after his long, brown hair was shaved with clippers.
Massachusetts Gov. Charlie Baker had his head shaved too.
Granite Telecommunications holds the event at its headquarters in Quincy. The company pledged to give over $5 million to the cancer institute if 1,000 people shaved their heads or beards.
Granite Telecommunications says 1,200 people participated and it'll contribute $6.5 million for its fifth annual event.
Brady says it was an honor to join the fun and support the great work of Dana-Farber.