Defender Tom McIntyre adds "quality and depth" to Aberdeen's squad after joining on a contract until the end of the season.
The 27-year-old arrives after two years at Portsmouth, where he made 14 appearances.
Former Scotland Under-21 international McIntyre spent the first half of this season on loan at Bradford, playing 11 games for the English League One club.
"When the opportunity arose to join Aberdeen, it was something I was really keen to make happen", said McIntyre.
"It's obviously a huge club and as a Scottish player I know how passionate the fans are here so I hope I can play my part in helping the team finish the season strongly."
McIntyre started his career with Reading and has made over 130 appearances in the English Championship.
"Tom is an experienced defender and he will add quality and depth to our defensive options where things are a little stretched at the moment," said Dons sporting director Lutz Pfannenstiel.
"He has a good pedigree and we believe he has the ability to make an impact for the club. He's eager to prove himself in the Scottish Premiership."
McIntyre's signing comes as the Dons confirmed defender Mats Knoester is out “short to medium term” after suffering a “serious” injury in Saturday’s defeat at Kilmarnock.
