The Spaniard has excelled in the Premier League since arriving at Spurs at the start of last season.
The 24-year-old can go back to Real as the club inserted a buy-out clause into the agreement that took him to Tottenham from the Spanish giants two summer windows ago.
According to El Nacional, Ancelotti wants president Florentino Perez to green light the €40 million transfer.
For his part, Reguilon has said yes to the move, as he wants nothing more than to make it at Real Madrid.
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