Pompey have signed 17-year-old Jed Wallace from Ryman Premier side Lewes.
The midfielder has signed a two-year professional deal, with the option of a further 12 months, and will initially come under the wing of Academy boss Andy Awford.
Wallace has already spent time training at Pompey and played in a behind-closed-doors friendly.
Awford said: “He’s a central midfielder with a good attitude. He’s a level-headed lad who wants to learn.
“This is the first step on the ladder – there is a lot of hard work in front of him. But hopefully he will blossom and come through the ranks.”