Our young defender played the full 90 minutes for the Republic's U21s in Monday's 2-2 friendly draw against Germany.
He followed that up with a training ground appearance for the U21s in a friendly against the senior side yesterday and is likely to stay in the line-up for Euro 2004 qualifiers against Albania on Friday and Georgia on Tuesday.
His international recognition comes after a successful loan spell at QPR that ended with a the Second Division Play-Off Final in front of a packed Millennium Stadium.
Our first team coach Chris Hughton, Ireland's senior assistant boss, was delighted for a player who he has watched come through the ranks at Spurs.
"Stephen has been drafted into the Under-21s, played against Germany and did very well," said Chris.
"He had a good spell at QPR and well in the Play-Off Final. He also played in the friendly against the first team and will stay in the Under-21s set up."
Ireland's U21s had three new caps including Stephen and U21 boss Don Given commented: "I think overall you couldn't single out anybody and the lads who came in gave us something. Our squad has changed a little bit now, the 1983 boys who have come in will be the experienced boys when we start the next campaign.
"They are learning at the moment from the big guys like Miller and Barrett but I am impressed with how they are playing."
Stephen Kelly has capped a season to remember by winning his first cap for Ireland Under-21s.