Centre-back Bruce played at under-21 level for the Republic and was also capped in two senior friendlies but, with the likelihood of further caps waning he began the process of switching to represent Northern Ireland under former manager Nigel Worthington.
His successor Michael O'Neill has now called the 28-year-old into a 24-man squad to take on Portugal in a World Cup qualifier in Porto on October 16.
Bruce was born in England but qualified for both the Republic and Northern Ireland via grandparents.
He was wanted by Northern Ireland at under-21 level but opted to play for the Republic.
He went on to captain their 'B' team and played for the full side in non-binding friendlies against Ecuador in 2007 and Poland in 2008.
He joins Hibernian's James McPake in the Portugal squad. The Scotland-born defender was persuaded by O'Neill to commit to Northern Ireland earlier this year and made his only appearance in the 6-0 friendly defeat to Holland. Both players will provide cover for the suspended Gareth McAuley.
There is no place in the squad for Lee Camp, the Nottingham Forest goalkeeper who left the squad for personal reasons after being dropped in favour of Roy Carroll for the first qualifier against Russia. Alan Mannus, of St Johnstone, and Michael McGovern of Falkirk will provide competition for the number one shirt but Camp's future is now in some doubt.
Elsewhere in the squad there is a recall for the country's record goalscorer David Healy, who is now back playing competitive football for Bury, as well as Peterborough's Grant McCann, who had declined an invitation to join a previous squad under O'Neill.
Bruce's Hull team-mate Joe Dudgeon, who has yet to be capped, is included, while Burnley striker Martin Paterson and Celtic winger Paddy McCourt both return from injury having missed the last two matches. O'Neill was unable to call on Chris Brunt and Jamie Ward (both hamstring).
Source: PA
Source: PA