The 19-year-old was called into the Young Lions squad by interim boss Paul Williams ahead of the Four Nations tournament during the recent international break, having impressed for the Magpies under-23 side in the last month.
Roberts headed straight off to meet up with his international teammates after United coach Ben Dawson delivered the news that he'd been included in his country's squad for the first time.
And the teenager - who picked up his first cap in the 2-0 win over the Netherlands at Oldham Athletic's SportsDirect.com Park - says it "didn't seem real" when he was first told of his inclusion in Williams' team for the competition.
"I was buzzing when Ben told me. I didn't know whether to believe him at first - it didn't seem real. But obviously it was, and it was a great feeling. I was so happy," Roberts told nufc.co.uk.
"He came into the changing room one morning. I hadn't a clue, but he just said 'I need a word with you'.
"He told me I was going away, and I said 'what do you mean?'. He said 'you're going away with England Under-20s' - I was so happy straight away.
"I wasn't expecting it. I'd seen the England squad, because I follow England on Twitter. I really didn't think I'd be getting a call-up now."
Roberts linked up with England along with Sheffield United's Louis Reed following the withdrawal of Rotherham United's on-loan Chelsea wideman Izzy Brown.
"I joined up with them a day or two later, but I didn't really miss much. I only missed one training session, so I was there for the whole week," he explained.
"Everybody was really good - the staff and the players were really good with me, and they made me feel welcome straight away."
That bow for his country came as a second half substitute in England's first outing of the tournament, where goals from Patrick Roberts and Adam Armstrong - himself a Newcastle player, currently on loan at Barnsley - got the Young Lions off to the perfect start against Holland.
And Roberts earned his second cap, and first international start, in the 2-0 win over the USA that sealed the overall tournament victory, admitting that taking to the field for England was a "surreal" moment.
"I played 20 minutes of the first game against the Netherlands, I sat the second game out against Germany and then I played 70 against the USA," he said.
"It was a crazy feeling, really. It seemed surreal. Playing for your country, representing the country, and knowing that there's only about 20 people my age who get to do that at one time was a crazy feeling."Roberts has now returned to Newcastle's Little Benton academy, where Peter Beardsley's second string are preparing to face Wolverhampton Wanderers in a Premier League 2 Division Two clash at Molineux on Friday night (7pm kick-off).
And having had a taste of life in the England set-up, Roberts says he has plenty of incentives to continue his fine form for his club, with next summer's Under-20 World Cup on the horizon.
"There's a lot of tournaments coming up. They're going to South Korea next month, which would be amazing to get into that squad, but to get into the World Cup squad for next year would just be even bigger," he said.
"Now that I've been away with them, I'll definitely keep thinking to myself that if I keep performing, then I can get back into the squad.
"But the focus is on Newcastle now, with Wolves on Friday. We're all focussed on that and getting the three points from there, because we want to get promotion."Beardsley's side go into Friday's clash in good spirits, having remained unbeaten in the league throughout September.
And former Gateshead loanee Roberts says his attentions are now back on helping United, who are just two points off the division's summit, continue to climb the table."We're unbeaten in three league games, and that's a massive confidence booster for the squad," he said. "After the Swansea game which we won, we want to carry that into Friday and see if we can get the three points now.
"I could say that I've got a lot of confidence at the minute. Playing the way I have played in the last few weeks was a massive confidence booster, but then getting the England call-up was even bigger.
"But I've got to keep focused, put that behind me, focus on the league and focus on the team and getting three points."
