Carlo Ancelotti's side were rumoured to be preparing a £197m bid for Mbappe on transfer deadline day, but the France international remained in his homeland after Paris Saint-Germain stalled over a move.
However, Mbappe is now expected to join Real on a free transfer in the summer of 2022, and Benzema has said that his compatriot has already given him his word over a move.
Speaking to L'Equipe, Benzema said: "Kylian Mbappe will join Real Madrid one day, I'm sure. I don't know when, but he'll come, it's only a matter of time. He said it himself."
Mbappe has started the 2021-22 season with four goals and three assists from eight Ligue 1 matches, bringing his total to 136 goals and 66 assists in 181 games for PSG. body check tags ::