Barcelona head to the Santiago Bernabeu on Saturday at the top of La Liga with a four-point advantage over their bitter rivals Real.
The Catalan team are yet to concede a goal in domestic action this year, prompting Ancelotti to suggest he has prepared something out of the ordinary to throw Luis Enrique's men out of their stride.
The Italian concocted a similarly off-beat move in the first Clasico of last season, when defenders Pepe and Sergio Ramos alternated in a defensive-midfield role in a side without a designated central striker, which did not have the desired effect.
However, Ancelotti claims his hugely successful managerial career contains plenty of instances where unusual strategies have worked.
"I will do something that will come as a surprise," Ancelotti told his pre-match press conference on Friday.
"This is something I like doing. I did it last year and it didn't work but I have done it many other times and I succeed.
"I have many thoughts as I am focused on the match but I also want to surprise people with the starting XI."
Ancelotti was at pains to point out that he meant no disrespect to opposite number Luis Enrique with a jibe about the early UEFA Champions League substitutions of Barca and Real stars Lionel Messi and Cristiano Ronaldo in midweek.
Comfortable positions against Ajax and Liverpool respectively meant Luis Enrique and Ancelotti were able to protect their prized assets, although when discussing the move, the Real boss referred to an incident in Barca's win over Eibar last weekend when Messi reportedly rejected a request to come off.
"No, absolutely not. I didn't mean to provoke Luis Enrique," he added.
"I respect him and his work a lot as I respect all my colleagues. If someone saw a provocation in there they are mistaken as that's not what I meant whatsoever."
