Teenage defender joins on loan.
The 18-year-old has already turned out in Colchester colours, having played in the Essex Senior Cup game against Concord Rangers at the end of October.
And he will now join up with the U's on a youth loan until January 12th 2015.
Jamie, who can play in central defence or at right back, has also played for Northern Ireland from U16s up to U21s level.
He is the latest player with Hammers connections to join up with the U's squad and teams up with Freddie Sears and George Moncur in the current U's set-up.
His move will be completed subject to paperwork clearance.