Richard Chaplow will spend the remainder of the season at Millwall.
The former England Under-21 international, who was also capped at Under-20 and Under-19 level, has struggled for regular first team action at Southampton this season, having made just three appearances since their return to the Premier League.
Chaplow, who made 25 outings as the Saints won promotion from the Championship last term, has now dropped down into the second-tier, having agreed a deal which will see him see the campaign out at Kenny Jackett’s Millwall.
As the 28-year-old wasn’t included when the St Mary’s club lost their FA Cup third round tie to Chelsea in the third round he isn’t cup-tied for the competition, meaning he is eligible to line-up against Wigan Athletic at Wembley in the semi-final next month.
Millwall have also taken striker Jermaine Easter for the rest of the season, but unlike Chaplow, he can forget all about appearing at Wembley as he appeared in CrystalPalace’s two third-round matches with StokeCity back in January.