Nick Jonas just got candid about one of the Jonas Brothers' biggest hits.

Nick recently celebrated the 15th anniversary of "S.O.S" by sharing a few "fun facts" about the smash single.

On TikTok, Nick revealed he was only 13 when he wrote the song "in a hotel room in New York City."

He also shared the original version of the song sounded very different than the finished track fans recognize today, explaining it "wasn't until we got into the studio with John Fields, our producer, that we were thinking, 'It needs to be more memorable right off the top.'" And so, that iconic guitar line was born.

But the song's sound isn't the only thing that changed. It also had a different title as first.

"It was originally titled 'A Call I'll Never Get,' and when it came time to make the track list for the album, everyone kept calling it 'S.O.S.' So, we went with that," Nick shared.

The song went on to become a huge hit.

"It was our first song to go to No. 1 on iTunes, I believe, back in '07. And, to this day, one of my favorite songs to play live," Nick added.

Kevin Jonas also commemorated the occasion by re-posting Nick's video to his Instagram Stories, while Joe Jonas decided to make his own video.

In his TikTok clip, he duets Nick's video while using the "What Fruit Are You?" filter. Watch below:

"S.O.S" was a huge hit for the Jonas Brothers. The song peaked at No. 17 on the coveted Billboard Hot 100, marking their first-ever Top 20 hit on the chart.

As of reporting, it has sold 1.5 million copies in the U.S. alone.

Watch Jonas Brothers' "S.O.S." Music Video:

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