Jordy Hiwula has extended his Pompey contract until the end of the current season.
The 26-year-old striker has netted three goals in five appearances since arriving on the south coast in October.
He bagged a brace at Cheltenham in the last round of the Papa John’s Trophy and also scored in the FA Cup rout of King’s Lynn.
Hiwula said: “I’ve settled in really well here and wanted to stay for the rest of the season, so I’m really pleased to have signed a new deal.
“On a personal level, I’m hoping to be involved a bit more, but will just take things one game at a time.
“We’re still in three competitions and looking to do well in all of them, although the aim has to be to secure promotion and we’ve got a set of boys here who can achieve that.
"I’ve settled in really well here and wanted to stay for the rest of the season, so I’m really pleased to have signed a new deal."
“It’s been a strange time with no games for a few weeks, but we’ve been training hard and are feeling fresh ahead of the FA Cup game at Bristol City this weekend.”
Blues boss Kenny Jackett added: “I’m delighted that we’ve secured Jordy’s services for the second half of the season.
“He’s an excellent finisher, with good movement and touch, and has been pushing our forward players for a starting place.
“I’m really pleased that he’ll be staying with us as we do our best to secure promotion to the Championship.”
Hiwula began his career with Manchester City and was part of the Coventry side that secured the League One title last term.