1) Giannou was at the centre of a tug-of war between Greece and Australia
The striker was born in Greece but raised in Melbourne, causing a rift of allegiances for the 26 year-old with both Australia and Greece vying for his services.
Despite playing for Greece against Turkey last year, Giannou opted for the green and gold, for whom he played for in the under 17's.
In a remarkable twist of fate, Australia confirmed two matches with Greece in Sydney and Melbourne, meaning Ginanou could line up against the side who gave him his international debut one year ago.
2) He has no problem finding the back of the net
Before leaving Asteras Tripoli, he was the club's top goalscorer with 13 goals in 21 appearances, and the second top scorer in the league.
Ange Postecouglou will be hoping his composure in front of goal and proven goal-scoring record will put the Socceroos in good stead to qualify for a fourth consecutive FIFA World Cup.
It was only fitting the Socceroos squad was announced in Oakleigh, Victoria where Giannou began his career playing for the Oakleigh Cannons.
3) The striker has already played under Socceroos coach Ange Postecoglou
Giannou played for the Australia under 17's while Postecoglou was in charge in 2006 and their relationship was key to him pledging his allegiance to the Socceroos.
"Giannou was selected in the last Greek squad so he obviously has talent. The Greek league is very defensive so his goal output is outstanding," Postecoglou said.
"I flew to Greece and had a chat to him and I'm really pleased to bring him in. I think he adds something to us.
"The inclusion of Giannou has been a long time coming and is culmination of two years of work."
4) He recently joined the ever-growing list of Australians playing in China
After spending the last nine years playing in Greece, Giannou has joined the likes of Tim Cahill, Trent Sainsbury and James Troisi in the Chinese Super League after joining Guangzhou R&F.
Coming off the back of a standout season at Asteras Tripoli, eyes will be on striker to continue his prolific form and strong performances for the Socceroos will only further his cause.
5) He is known as 'Paul' in Melbourne
Just to clarify for people in Melbourne, "Paul" Giannou made waves playing at the Victorian Institute of Sport under Ian Greener, and attracted the praise of his former coach.
"Paul was a fantastic player who had an abundance of quality and was a greater striker of the ball who had sound technique and awareness," Greener told The Corner Flag.
"He had the ability no matter what position he was asked to play in and was very coach-able in that he'd listen to instructions and always sought to improve his performance.
"He had a determined attitude and I'm pleased for him as he had the ability and always wanted to be a professional footballer."