Gary Mackay-Steven has signed a two-year deal with Dundee United after impressing on trial.
Skysports.com revealed earlier on Tuesday that a deal was in the pipeline and the former Liverpool youngster has now put pen to paper.
The 21-year-old, who has previously played for Ross County and the Reds before joining Airdrie in November 2009, has shone in pre-season training and in friendlies.
He will travel with the squad to Poland for the Europa League game against Wroclaw on Thursday.
Manager Peter Houston told the club's official website: "He's a winger who has fantastic pace and skill and can deliver great crosses but he still has a lot to learn.
"We don't play with out-and-out wingers so he would have to learn to play the way we like to but I liked what I have seen so far.
"There is great potential there and Gary has performed well in both training and pre-season. He is a welcome addition to our squad."