A Pentatonix member is leaving the group

And then there were four...

Sadly, a capella group Pentatonix has announced that Avi Kaplan will be “taking a step back” from the band in a tearful video posted to Facebook.

Flanked by his fellow band mates Scott Hoying, Mitch Grassi, Kirstin Maldonado, and Kevin Olusola, the singer revealed that he’s been grappling with the choice for a long time — calling it the “one of the toughest decisions I’ve had to make in my entire life.”

The singer revealed that he misses his friends and family as well as not being able "to escape into nature when I’m feeling overwhelmed or just need some time to myself."

He went on to thank fans for the years of support, saying “it far surpassed anything I could have ever dreamed for my life.

However, he plans to fulfil his commitments to the band's upcoming world tour, but after their last stop in September he will finish up.

The group first burst onto the music scene in 2010 after winning season 3 of NBC’s The Sing-Off.

Since then they’ve produced a number of high-profile collaborations and tribute performances.