Pompey have signed 28-year-old forward Aiden O’Brien from Sunderland.
The Republic of Ireland international has put pen to paper on a deal until the end of the season.
He came off the bench for the Black Cats in their narrow victory over Pompey at the Stadium of Light earlier this month.
Blues boss Danny Cowley said: “We’re really pleased to sign Aiden and from the moment I spoke to him, there was an energy and enthusiasm to join us.
“We’re lucky to be at such a renowned football club because there are so many players who want to come here.
“Aiden brings us many different qualities and can play across the forward line, making penetrative runs.
"We’re really pleased to sign Aiden and from the moment I spoke to him, there was an energy and enthusiasm to join us."
“He looks after the ball well and links the play, while he can also drive forward and is always a goal threat.
“We’re really looking forward to him being part of this group and he knows quite a few of the lads already, which is important when you arrive on a short-term contract.”
O’Brien signed for Sunderland in the summer of 2020 and netted 12 goals in 66 appearances during his time on Wearside.
He joined them from Millwall, where he progressed through the ranks and featured on 226 occasions.
O’Brien appeared alongside Mahlon Romeo, Shaun Williams and Ryan Tunnicliffe for the Lions and helped secure promotion to the Championship via the play-offs in 2017.
He has been capped five times by his country at senior level, scoring in a 2018 friendly draw in Poland.