Jimmy Fallon says filming his Puerto Rico special was a ''punch in the gut''.

In January, the 44-year-old host visited the unincorporated US territory with his pal Lin-Manuel Miranda to film a special version of 'The Tonight Show Starring Jimmy Fallon' on the island in order to shine a light on recovery efforts after two devastating hurricanes in 2017.

The comedian explained that visiting the country was a ''game changer'' and insisted it was ''honestly insane'' to see the ''catastrophic'' condition the country was left in after the natural disaster.

In an interview with Deadline, he said: ''So, we went down there and, dude, it was a game changer. It really was a punch in the gut. People were crying and hugging me, and it was honestly insane, how much they were appreciative.

''Like, ''Wow, somebody thought about us. I can't believe this is happening.'' It's awful, dude; you can't even imagine.

''It takes years to rebuild after such a tragedy ... It's catastrophic. If you have a family, and no power for months, no running water, no roof, and it's raining on you ... What's going on?

''So, this little drop of something - some entertainment, or something just to go, 'Hi, we see you guys.' It meant a lot to those guys, and it meant a lot to us, too.''

Jimmy went on to explain that it was his friend Lin-Manuel, 39, who inspired him to visit Puerto Rico after he took his hit Broadway show 'Hamilton' to the country for a special performance to raise awareness ''that Puerto Rico exists''.

He said: ''The Puerto Rico show was inspired by Lin-Manuel Miranda, who was taking Hamilton down to Puerto Rico, to just basically raise awareness that Puerto Rico exists, and they need help.

''I was like, 'Jeez, if you can move a Broadway show to Puerto Rico - not only a Broadway show, but a hit Broadway show - [To] move it anywhere is near impossible; there's so many things involved with that. But he pulled it off, man. And I was like, 'That's inspiring. We've got to do something. Can we do one show?' ''