Transcript for The making of 'Despacito' and its rise to be summer's top song
Reporter: It was the inescapable song of the summer. Dominating the charts, infecting our brains with its undeniably catchy hook. Capturing the world's attention, reaching number one on billboard's top 100 and staying there for 16 weeks. ??? Reporter: The first mostly Spanish language song to reach the top spot in over 20 years and outside the Latin music world most have not heard of Luis fonsi. You are a 20-year overnight success. That's exactly it. Does it feel fresh? It does. It feels like this is my first album and I'm new to the game. Reporter: Fonsi is no stranger to chart topping hits. A Latin grammy award winning performer known for ballads like this one. ??? but it was despacito that helped him reach an international audience including none other than Justin Bieber who says after dancing to the song he wanted in. ??? We had a full-on English translation and vocals recorded in English and we thought he was going to the an English version. But he took the time to learn in the Spanish. People are impressed with Bieber's Spanish accent. It's legit? It is legit. Reporter: Fonsi said it is a dream come true that started with a simple rhyme. I had this melody and and this word. And I had to rhyme Puerto Rico which is where I'm from and I had a writing session that afternoon. Reporter: Ek ka ender is a Latin grammy award winner herself. I start playing it for her. And we started to make the whole thing from scratch. And four hours later we had despacito. We knew it had to be urban fusion in a certain way. That's what's going on right now. Reporter: And that's where daddy Yankee came in. Then I tell him, why don't we talk about a man that is trying to get to a woman in a very nice way because this genre is very aggressive with women and this song is respectful. Reporter: The video's director says fonsi had a simple, yet poignant idea for the video. Like a day in the life of the culture of Puerto Rico. We're talking about who the lead could possibly be we all knew it had to be someone who felt credible in the environment and above and beyond all, really was a true representative of the beauty in the caribbean. Reporter: If showcasing Puerto Rico's beauty W the goal, zuleyka Rivera was their answer. He said I just want you to feel the music. I just want you to be here. Walk from here to there. And just feel the music. ??? whatever you feel about the song, just do it. So pretty much I was freestyling. Ms. Puerto Rico! Reporter: That's her in 2006 being crowned miss universe bringing home the win for Puerto Rico. The dress in the video a nod to that pageant dress. Everybody is having a great time, dancing and so happy. And that's what you see in Puerto Rico. Every time you go to Puerto Rico. Reporter: Turns out the single most watched YouTube video of all time with 3.7 billion views and counting -- was all shot in one day. And edited here in this small studio in Miami. The finished product? ??? a song so infectious it inspired van videos from around the world, translated into dozens of languages. ??? Reporter: Even sesame street with their version. It's been like a fever. It's crazy. This feels like a love song to Puerto Rico. I think the star of the show is Puerto Rico. It's a special place. And it's an inspiration behind my music. And now to be able to sort of represent Puerto Rico through my music is a dream. Reporter: Fonsi was named tourism ambassador for his beloved Puerto Rico, his song used to lure visitors. We begin with a monster hurricane gaining strength in the atlantic. Reporter: Puerto Rico was battered by hurricane Irma, leaving a third of the island without power. As fonsi put out this warning. And later joining other celebrities to raise millions in relief, all part of the hand in hand telethon. ??? as the island braces for another hurricane this week the video is now serving as a reminder of what's under threat. And yet at the same time for the creators, it's a heart felt ode to their Puerto Rico. It doesn't matter language. It doesn't matter the culture. It's to enjoy life. Exactly what you see is what everyone was feeling. I'm just thankful to know that 3 billion times people saw this video and sang the song and saw the beautiful sights. Reporter: And for the rest of us, a reminder of the summer that was.
This transcript has been automatically generated and may not be 100% accurate.