Benzema 'motivated and enthusiastic' despite World Cup misery
Ballon d'Or winner Benzema was selected in the French squad for the World Cup in Qatar but a thigh injury in training saw him forced to withdraw before the opening game.
He then announced his retirement from international football following the tournament where France were runners-up to Argentina.
"I don't want to say anything about the decision that France made. They said he couldn't play at the World Cup. We saw a guy come in both motivated and enthusiastic," said Ancelotti of a player who has racked up more than 600 matches in 12 seasons in the Spanish capital.
"He will be a great help over the second part of the season."
Benzema had been desperate to feature in this year's World Cup having not been selected when France became world champions in Russia four years ago.
He was frozen out of the France team for five and a half years because of his involvement in a blackmail scandal over a sextape involving his former teammate Mathieu Valbuena.
In a trial over the affair last year he was handed a one-year suspended prison sentence and fined 75,000 euros (£72,500).
Benzema scored 37 goals in 97 appearances for France.
Real Madrid resume their La Liga season on Friday at Real Valladolid where victory would see them leapfrog Barcelona at the top of the table.
