The Welsh winger has rated the former Motherwell, Everton and Birmingham City forward as a top player and said his presence at Parkhead would be a great boost for the Hoops who have slid 10 points behind Old Firm rivals Rangers on the Scottish Premier League table.
"He's a great player and I think he would be good for the team," Ledley said of McFadden who is being tracked by Everton and Wolves.
"Obviously it's down to the club to sort it out but we would welcome him to the club.
"I've seen him play for Scotland many times and he's a great player.
"It's down to the board and the manager if they want to bring him in but we would welcome him straight away as we know he's a great player. He would suit the way we play.
"I remember his goal against France in Paris and I can imagine how big a moment that would have been in Scotland.
"That just proves how big a player he is. He can score good goals but he's a great playmaker as well.
"If we're interested then it's up to him to decide if he wants to come. It would be nice if he did pick Celtic over other clubs."