The 22-year-old Nigerian winger signed for the Ukrainian giants from current league leaders LNZ Cherkasy.
He joined LNZ from Portuguese side Vizela and has gone on to score eight goals in 17 games in all competitions with four assists.
Prosper told his new club: "I haven't spoken to anyone about my transfer yet. For me, it's just incredible. I feel great. It's a big step for me, so I'm very happy! Good feelings.
"Of course, I was pleasantly surprised. Shakhtar is a big club, so when I found out about the interest, I was a bit surprised.
"I hope to help the club win titles – in Europe and the Ukrainian Championship. And I want to personally contribute to the team with my decisive actions."
Chelsea forward Mykhailo Mudryk has reportedly passed a lie detector test in connection with an ongoing investigation into a failed drugs test, with Shakhtar Donetsk's chief executive asserting that the player did not knowingly commit any wrongdoing.
Borussia Dortmund have confirmed that interim coach Mike Tullberg will continue to lead the team for their upcoming Champions League match against Shakhtar Donetsk on Wednesday.
Bayern Munich boss Vincent Kompany believes his side dominated Shakhtar Donetsk in their 5-1 UEFA Champions League victory on Tuesday.
Mikel Arteta has admitted Arsenal looked fatigued in their narrow 1-0 Champions League win over Shakhtar Donetsk at the Emirates.
