St Mirren have signed 20-year-old attacking midfielder Kieran Sadlier until the end of the season.
Manager Gary Teale told the club website: "Kieran has had a good development at West Ham and also being involved with the Irish U21 team.
"He was very keen to come up to Scotland when I spoke to him before the transfer window closed and negotiated his release from West Ham to come up to St Mirren.
“He showed great enthusiasm and ambition that he wanted to play first-team football - hopefully he will be of great benefit to ourselves going forward.”