The player formerly known as Tomas Gustafsson looked to set to spend this summer in his native Sweden.
But he was called into the Swedish squad to face Norway on 17 April and looks to have settled the Scandanavian outfit's problem position of right back.
Antonelius' rise has been dramatic.
The 20-year-old had been at Division One side Coventry City but opted for a switch to FC Copenhagen in a bid to impress Sweden's selectors.
He signed a three-and-a-half year deal with the Danish champions and has grown in stature since then.
Prior to the April friendly his last international appearance had been in the 2-1 loss to Italy at Euro 2000.