ET's Kevin Frazier caught up with the Hamilton creator on Tuesday at the TIDAL X: Brooklyn Benefit Concert at the Barclays Center in New York City, where he marveled at his friend's performance.
"He's unbelievable. As soon as I saw he was participating I said, 'Well, I know who's winning this year,'" Miranda, 37, shared. "That kid's a star. We all know it, you know it, the American people know it."
Miranda said he was "really grateful" that Fisher -- who starred as John Laurens and Philip Hamilton in the acclaimed Broadway musical -- chose their song from Moana for his DWTS Disney Night routine.
"I'm grateful to be here and again, there's no shortage of ways to do good in the world. There's no shortage of challenges that need ordinary people to good," he said, sharing his thanks to Tidal, the artists who turned out to perform and everyone who has contributed to their ongoing efforts. "We're all helping each other out and that feels great."
Hurricane Maria came on the heels of Hurricanes Harvey and Irma, which tore through Texas, Louisianna and Florida within days of each other. Maria left Puerto Rico in a state of total devastation -- and Miranda is among numerous public figures to point out the apparent discrepancy in the government's response between the disasters.
"We rushed to help Texas, deservedly so, we rushed to help Florida, deservedly so -- those are our brothers and sisters -- and Puerto Rico is home to 3.5 million more American citizens and yet what was sent there was not commensurate with the two previous hurricanes," Miranda explained. "And now we're running at a deficit as a result."
Miranda has spent weeks encouraging those who wish to help the relief efforts in Puerto Rico to donate to The Hispanic Federation, which has designated 100 percent of its Hurricane Relief Fund to Puerto Rico's recovery efforts. Click here for more information on how to contribute.