The 27-year-old stopper will provide defensive cover for ’Well backline regulars Peter Hartley, Cedric Kipre and Charles Dunne in the second half of the season.
Aldred, who formerly played four games in the Scottish top flight when on loan to Inverness Caley in 2011, said: “I am really looking forward to it, to getting my head down, working hard and being the best I can be for the football club.
“Playing in the Scottish Premiership was something I was really interested in. I’m looking forward to getting going.
“I am familiar with Scotland. My mum’s side of the family are Scottish and I’ve visited up here a few times.
“Obviously with them doing well in the cup as well. I know a few of the boys as well I’ve played with, and against, in England.
“Wherever you go now, there’s competition for places,” he said. “Anywhere you go at any team, at any level. The more competition, the best it brings out in yourself.”
Aldred started his career with Carlisle United in 2008, before a move to Watford two years later.
After loan spells with Stockport County and Inverness CT, Aldred moved on to Colchester United, with further temporary stints at Torquay United and Barrow.
Regular games followed in 2012 after a move to Accrington Stanley, where he made 94 appearances before a move to the English Championship with Blackpool.
A regular with the Seasiders over the course of three seasons, the towering defender was their captain as they won the League Two play-off final last campaign.
A move to Bury followed in the summer under former Kilmarnock boss Lee Clark, where he made 23 appearances this season before the switch to Fir Park.
And Motherwell manager Stephen Robinson was understandably delighted to add an experienced defender to his squad, as Motherwell gear up for their return to competitive action in a home William Hill Scottish Cup derby encounter against Hamilton Accies this Saturday.
“We were clear from the start of the January window we were looking to increase our options in central defence.” manager Robinson said of his signing.
“Tom ticks that box and arrives at the club with plenty experience under his belt.
“We tried to get him in the summer, so we are delighted to finally have him at Motherwell.”
’Well fans are hoping that Aldred can inspire the Steelmen to their first win in 10 matches this Saturday.