The 27-year-old made just nine Premier League starts last season after falling out of favour with Villa boss Paul Lambert, with the likes of Ashley Westwood and Fabian Delph preferred in central midfield.
But he has now sealed a temporary move away from the club, reuniting with manager Mark Hughes, whom he worked under during his time at Manchester City.
"Stephen is a player that Mark knows really well and when the opportunity arose he was keen to add him to his midfield and attacking options," chief executive Tony Scholes said.
"Arguably the most successful period of Stephen's career to date was when he played for Mark at Manchester City and we hope that he can rediscover that form."
Ireland has made 233 appearances in his career, scoring 24 goals.
Stoke have also announced that they do not anticipate any further business before the close of the window.
