Both Madrid clubs are vying to sign bring Chelsea left-back Marcos Alonso back to Spain, according to AS.
Alonso is actually a former Real Madrid player, having turned out for the club's youth academy and then the Castilla side. He made just one appearance for the Los Blancos first-team, replacing Gonzalo Higuain as a late substitute against Racing Santander in 2009.
The 27-year old ended up turning out for Bolton Wanderers and Sunderland before getting his big move to Chelsea in 2016 - and his since built himself his career back up to the point where two of Spain's big guns want him.
Atleti and Real are said to be keeping tabs on Alonso and both reckon they can nab him for an extremely affordable 30 million euros.
With Filipe Luis potentially joining Paris Saint-Germain, Alonso has emerged as Atletico's number one choice for the left-back berth.
Meanwhile, Real have loaned out Theo Hernandez and are in need of top-quality cover for Marcelo. Alonso is also versatile enough to do a job at centre-back, which is of great use to Real boss Julen Lopetegui - who worked with him while he was coaching the B team around 10 years ago.
The transfer window in England shut before the season began but clubs in Spain are still able to sign players so a late push for the former Fiorentina man. Failing that, it's expected that the pair will still remain interested in Alonso beyond the summer
Alonso was named in the PFA Team of the Year last season and has continued his fine form into the new campaign - notching the winner against Arsenal at Stamford Bridge on Saturday.