Left back signs on a two year deal.
Prior to his stint with Millwall, Matthew had been with Fulham since he was eight, and made thirteen senior appearances for the Craven Cottage side during his time at the club.
Matthew has signed a two year contract and joins fellow full back Richard Brindley in converting his loan switch to a permanent move.
Matthew enjoyed a successful loan spell with the U's at the tail end of the 2014/15 season and, after leaving Millwall at the end of that campaign, he has now signed for the U's on a free transfer.
Colchester United have made their third addition of the close season with the permanent capture of defender Matthew Briggs.
The 24-year-old was the youngest ever Premier League player when he made his debut at just 16 years and 65 days.
Whilst with Fulham, he had loan spells at Leyton Orient, Peterborough United, Bristol City and Watford, before joining Millwall in the summer of 2014.
Matthew has also represented England at every level between U16s and U21s, before opting to play for his family's country of heritage, Guyana, at senior level.