The pompey striker who will be 23 on the 3rd October has signed on a three month loan deal with a view to a permanent move.
He has endured a two year absence from the South Coast side due to injury but has since recovered.
"I really am very pleased because Vincent has always been one of my main targets but he wasn't available because he wanted to break through again with his club," he told the club's official website.
"It was disappointing at the time but I kept pestering him and I suppose my patience has been rewarded.
"He's an athletic type, a good target man with a great touch and has some pedigree with having been with Juventus. If things go well during his stay then we could be looking at a permanent deal." Said Neil Warnock.