Get ready to feel old!

Hanson has been a band for 25 years. Their oh-so-catchy 1997 hit Mmmbop, which apparently no one knows how to sing correctly , is officially 20 years old. Thats right, 20.

To celebrate both their major milestones and the launch of an upcoming world tour, brothers Isaac, Taylor and Zac stopped by Good Morning America to perform the song that started it all. Mmmbop hit the top of Billboards Hot 100 when it came out, and somehow, it still stands up.

The nostalgia is real.

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