Harvey Rew has signed his first professional contract with Pompey.
The 17-year-old academy defender has penned a two-year deal, with the club holding an option for a further year.
Rew – who can also play in midfield – is yet to make a first team appearance for the Blues, but has represented Wales U16s and U17s.
Academy manager Mark Kelly said: “Harvey has shown plenty of promise, with some really consistent performances at academy and international level.
"Harvey is a Pompey boy and really wants to play for this club."
“This contract is well deserved, but there’s still a long way for him to go and this is simply the next step on the footballing ladder.
“Other sides have been looking at him, but Harvey is a Pompey boy and really wants to play for this club.”