The 25-year-old is part of the Netflix series 'We are Newcastle United' which will be released later this week.
It gives a 'fly on the wall' insight into Newcastle's 2022/23 Premier League campaign, as the Magpies finished fourth - securing Champions League football.
There was one story in particular that does not feature in the documentary, which Longstaff is glad for.
"A lot of us went on holiday together in the summer, so we're with each other a lot," he said.
"When we got back and had a couple of weeks apart, everyone hated it - we couldn't wait to get back training!
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"We went to Las Vegas - me, Nick Pope, Paul Dummett, Mark Gillespie, Matt Targett, Jamaal Lascelles, Fabian Schar, Loris Karius… just as well the film crew didn't follow us there!"
On a serious note, though, he said players ended up not noticing camera crews as much.
"The makers [of the documentary] were really good. We didn't notice them as much as we thought we would.
"The crew felt like part of the team come the end - they were in giving us handshakes after we'd won, it was a bit weird! I'm just hoping we all come across ok!
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"But I'm just a little fish, so they weren't really following me around. I'll leave that to Popey and Tripps (Kieran Trippier). I just got to glide by. At one point I was thinking, "Am I ever going to get on this thing?"
Part of the new series offers an insight into the Eddie Howe' rallying cry, prior to Newcastle's 2-0 victory over Manchester United.
Erik ten Hag had claimed Howe's men were good at slowing the game down, comments that certainly riled the Newcastle boss.
"If they want a quick game coming here, let's f***ing give it to them,' said Howe in one part of the series.
"Let's blow them away with our running. Let's be intense with every action we do. Let's make it a quick game. Let's go!"
Newcastle kick of the Premier League season at home to Aston Villa on Saturday 12 August.