Tony Craig has joined Millwall from Brentford, three years after he made the opposite move across London.
The 30-year-old leaves the Bees after they agreed to terminate his contract so that he could join the Lions on a free transfer.
"The last time I left I thought that I had played my final game for the club but I'm back now and ecstatic," Craig told Millwall's website. "I really am looking forward to having the opportunity to continue my Millwall career."
Brentford co-director of football Phil Giles added on the Brentford website: "He was a key part of the effort to establish Brentford as a Championship club.
"Although I personally didn't work with Tony for very long, I've heard several stories of how he went beyond the call of duty in order to play. He was a leader in the dressing room."
Craig was an ever-present for Brentford in his first two seasons as a Bee, helping them to promotion from League One in 2013-14 before appearing in half of their Championship matches last term.
