Millwall boss Harris hailed the capture of the club legend, which is being touted on Twitter with the hashtag #TheReturn.

"I'm naturally really pleased," Harris told the club website. "First and foremost, Tim comes with a wealth of experience. Not just in the footballing world, but for this football club. It might have been just over 13 years since he left, but this place doesn't change.

"There's still the same morals and principles and it's a workman-like football club. Tim has been around the world playing, but his attitude, his discipline and his lifestyle hasn't changed one bit. In so many ways, he is still the kid I used to share a dressing room with years ago.

"The players will thrive off the enthusiasm that he brings. When I played with him, I appreciated what he did. Since then, I've followed his career and admired what he has done and I know full well what he can bring to my dressing room.

"He is a different player to what he was years ago - he plays a little higher up the park now. At 38, he is in terrific shape. To start with, we are thinking about impact - someone to come off of the bench and give us that little lift, someone to lift the crowd and someone to pass on that knowledge when in front or behind."

Harris said Cahill was determined the make the move, despite reported late interest from both QPR and Nottingham Forest.

He added: "I'm really pleased. It's taken us January to get there, but the reason we're here is because of Tim's committment to come. He had lots of offers, lots of places around the world that he could've gone to, but he chose Millwall. I'm delighted to be bringing him into the squad."

"What he will bring into the dressing room is standards and leadership. He lives his life in the right manner. He'll be the first in and the last to leave. He'll add to the leadership we already have at the club in Steve Morison and Tony Craig. Because of the shape he is in, he'll demand everyone is at that level.

"At 3pm on a Saturday afternoon we'll have a benefit, but from 9-5 every day of the week, he'll have an input."