Fairhurst scored on his full debut against West Brom last week and added another in his second start for Rovers in the 3-3 draw against Ipswich and O'Kelly believes Sheffield United forward Sharp has helped bring out the best in the 20-year-old.
O'Kelly said: "Waide (Fairhurst) got into a good area for his goal and that's something we spoke about.
"He and Billy have worked well together again, so we were pleased with that.
"Waide has now scored two in two games and I'd imagine that Billy has had an influence because he's affected the game.
"We're pleased with Waide. Ever since he came into the professional ranks he's shown loads of enthusiasm and he's worked hard."