Louis Dennis has completed a move to Leyton Orient.
The Pompey forward has been sold to the newly-promoted League Two side for an undisclosed fee.
The switch comes shortly after Blues boss Kenny Jackett admitted there were several clubs interested in the forward.
Dennis joined the Blues on a free transfer from Bromley last summer.
However, he endured a difficult maiden season at Fratton Park.
He featured only eight times, with just one of those appearances arriving in League One, and was behind the likes of Brett Pitman and Gareth Evans in the number-10 pecking order.
Despite Dennis starting pre-season brightly, scoring two and creating two goals in the 11-0 romp at UCD, he was an unused substitute at Crawley on Saturday.
The forward was then left out of the squad for Tuesday's 4-2 win at Woking – but is now expected to go straight into the Leyton Orient squad for their season opener against Cheltenham on Saturday.
O’s interim head coach, Ross Embleton, admitted the Brisbane Road outfit had been tracking on the 26-year-old for some time.
He said he was looking forward to unleashing a player with ‘natural ability’ on League Two defences this season.
‘It’s taken us a massive chunk of the summer to finally get here, Embleton told leytonorient.com.
‘Louis has been a player we’ve admired at the club since we came up against him in our first season in the National League.
‘He got a fantastic move to Portsmouth but as soon as we got the opportunity to bring him to this club it’s one we began to pursue.
‘His natural ability and talent, when you look across all levels of football, the players that make you sit up and get up out of your seat.
‘Those ones that have that extra bit of ability and the talent to go past people and make something happen – Louis has certainly got that.
‘We’ve watched him on a number of occasions, studied all of his footage and he is a player of real ability.
‘So we’re going to allow him to go out there and express himself like we do with all the players.
‘But he’s got the natural ability that will hopefully excite people.’