Armstrong, 18, is a lifelong Newcastle fan who has come up through the ranks with the Magpies, establishing himself as a regular scorer in the club's youth and reserve teams during his time at the club.
With 15 first team appearances last season, it's clear that the teenage striker is highly-rated on Tyneside, but having signed Aleksandar Mitrovic earlier this summer, Armstrong has been sent out on loan to continue his development elsewhere.
Armstrong has been sent to League One side Coventry City on a youth loan until January, which will allow him to play regularly and give Newcastle the chance to re-asses in 2016.
The youngster is already showing Newcastle what he can do, as after two games for Coventry, he has already scored four goals in what has been a sensational start to his loan spell at the Ricoh Arena.
Pundit Peter Beagrie, who played for Newcastle's North East rivals Middlesbrough, told Sky Sports just how impressed he has been with Armstrong so far, and added that the Magpies coaching staff continue to rate Armstrong highly.
"He has such a low centre of gravity, very quick, mobile and clever with his runs," said Beagrie. "I have a lot of friends in the coaching staff up at Newcastle and he is highly regarded. Tony Mowbray can spot the player. He built a very young, vibrant side at Hibernian, and that is exactly what he is doing now."
"Armstrong has grasped his opportunity and has been a revelation. He plays with no fear, and will try anything. A couple of braces and a goal of the season contender already is incredible. With a manager who will back him to the hilt, on a perfect surface like Coventry and with his enthusiasm, he will go far," he added.
Armstrong has also hit 21 goals in 29 games for England at various youth levels, showing his potential on a regular basis for the Three Lions.
If Armstrong continues to impress at Coventry, he will earn an opportunity to feature for his boyhood club Newcastle - and as Harry Kane has shown at Tottenham, that one chance can lead to senior international recognition.