New Pompey deal for Vine
The 21-year-old is spending the entire campaign on loan at Layer Road, having made 40 appearances and scored 12 goals for The U's this season for the Second Division club.
It is Vine's second season of Division Two football, as he spent the last campaign on loan with Brentford.
His performances for the Essex outfit have prompted Pompey to secure his services for a further two seasons.
"We've agreed two more years with Rowan Vine. It's an extension to his existing contract," revealed Fratton Park chief executive Peter Storrie.
"The manager feels he is a player who has a future here (at Portsmouth)."
Despite signing a new contract with the Premiership club, Colchester chief executive Marie Partner believes there is a chance Vine could return to Layer Road for next season.
"Much of course depends on the manager's (Phil Parkinson) plans for the transfer market this summer," Partner told the club's official website.
"But there is nothing to stop him returning for Rowan with a view to a similar move for next season."
Meanwhile, The U's have handed trials to two youngsters from non-league Dulwich Hamlet.
Defender George Elokobi and striker Ellis Green played in the club's reserves this week, as they try to impress their way into league football.