The pair were drawn together in the final four last Friday, while the other semi-final will be contested between Atletico Madrid and Chelsea.
"I know they're not happy playing us," Ancelotti told El Mundo.
"All the teams in the draw were complicated opponents, each with their own style. In addition, the Champions League is a treacherous tournament, very hard to win, and strange things can happen."
Bayern are the current holders of the Champions League.