The Dublin-born forward, the top scorer in League One last season, was initially put on standby for the friendly with Wales in Cardiff on Wednesday after a string of attacking injuries.
But, after Ireland's assistant manager Marco Tardelli watched the former Carlisle man against Birmingham on Saturday, the 23-year-old was handed a call-up.
"I am so proud to be called up to the squad," he told the club's official website. "This is something I have dreamed about since I was a small lad.
"I know a few members of the squad having played with them at other levels for Ireland. I cannot wait to meet up with them all and fingers crossed I get to show everyone what I can do."
Madden is yet to find the target for the Glovers this season having rattled in 23 goals in 2012/13.