We watched as they auditioned on "X Factor," became a boy band, released chart-topping songs and overtook stadiums worldwide. For Gen Z and millennials who grew up alongside the British boyband One Direction, the death of singer Liam Payne is especially devastating.

Even for those who were not "Directioners," Payne's death comes as an overwhelming shock, and for Gen Z, it feels like the first major collective loss for our generation.

People have flocked to social media to share their grief.

"I actually am in shock and had to pause mid work meeting to not cry," one fan wrote. "Wow. 12 year old me is shattered into a million pieces."

Another tweeted: "I feel like most of us are so shocked over liam payne's death (because) that man once was part of something our 13 year old selfs could never imagine living without. like why am i actually speechless right now."

What is 'collective grief'?

Celebrity deaths can feel personal, even if you never met the person. And while grief is different for everyone, experts say collective or public grief is a valid experience and can be exacerbated when the death of a public figure is learned unexpectedly in the news or on social media.

"When people experience sudden loss, they may feel shocked, disbelief, confused, and even in denial," Shavonne Moore-Lobban, licensed psychologist, previously told USA TODAY. "The suddenness of the loss may be too much to process and feel too unreal for a person to immediately grasp."

Many people also experience parasocial relationships with celebrities, a phenomenon frequently associated with fan culture, which can make a public figure's death feel even more real.

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One Direction blew up during the rise of social media and was one of the first bands that fans had constant access to, making the five boys feel like a part of their lives. Fans could rewatch an interview on YouTube countless times or deep-dive into their tweets, spending hours "with" and obsessing over Payne and his bandmates.

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"It's a fascinating thing that people don't realize we really can grieve people we didn't know,"  David Kessler, grief expert and founder of Grief.com, previously told USA TODAY. "And it doesn't mean we're going to grieve them like our spouse or mother, father, or sister or child, but we will grieve them."

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If you are struggling with feelings of sadness, confusion or grief, help is available. Call or text 988 or contact the Crisis Text Line by texting HELLO to 741-741.

This story was updated to add a video.