Neil Harris claims Alex Pearce will bring crucial 'leadership qualities' to the Millwall camp after securing the centre-half as his first January signing.
The 30-year-old centre-half has played in the Premier League and won the Championship title with Reading, and arrives at The Den on a loan deal from Derby County.
"Pearcey brings a wealth of experience," Harris told millwallfc.co.uk.
"We've lacked a little bit of leadership at times in games where we've let late goals in or conceded too many goals, and we've needed that presence in there at the back.
"We had it in the second half of last season with Jason Shackell, and we've had it in the past with Tony Craig as well. I just feel that Pearcey brings us a voice and leadership in training, and that's not forgetting what a good career he's had so far at this level."
The manager is excited to work with the Republic of Ireland defender, and is looking to maintain strong competition for selection in the back line. Harris also touches on Pearce's chances of making his Den debut on Sunday against Hull City.
"I think competition for places so far in this position has been key and we'll try and build that, and we look forward to working with him.
"We'll have a look at him in the next couple of days in training, and then we'll decide our options."