Benzema, the reigning Ballon d'Or, swapped the Santiago Bernabeu for Saudi Arabia in June after 14 seasons in Madrid, where he is second on the club's all-time goalscoring list with 354 - trailing only Cristiano Ronaldo. In a bid to bridge the 10-point gap that separated them from Barcelona last season, Madrid splashed out 103 million euros on England international Jude Bellingham and swooped for Turkish prodigy Arda Guler.
But Mbappe, who has scored 212 goals in 260 games for Paris Saint-Germain, is the player they have long targeted. After missing out on the France captain last year as he agreed a new deal to stay in Paris, Madrid again appear the likely destination for Mbappe, who is locked in a contract dispute with PSG.
Mbappe is training with PSG's reserves and has been told he must sign a new contract if he wants to remain with the French champions this term. PSG are thought to suspect that Mbappe has already struck a deal to join the Spanish giants for free in June 2024, but Madrid coach Carlo Ancelotti has been reluctant to broach the subject publicly.
Mbappe "is a player who is not at Madrid," Ancelotti said last month. "To talk about players who are not here, it doesn't seem right to me."
Can Barcelona replace Busquets?
Centre-back Inigo Martinez has arrived from Athletic Bilbao, with Oriol Romeu returning to his boyhood club as what Barcelona hope will be a low-price replacement for Sergio Busquets. The loss of the influential Busquets, who joined Messi and Jordi Alba in Miami this summer, is one of Xavi's greatest worries.
"A player who has been so important for us, on and off the pitch... we have to find a very important player to replace Busquets," Xavi said in May. "We have to find this piece, if we want to compete well." French winger Ousmane Dembele is also poised to leave Barcelona after receiving an offer from PSG.
Atletico Madrid finished third last season, just a point behind their city rivals after a vastly improved second half, and hope a reinforced defence can strengthen their title prospects. Cesar Azpilicueta signed from Chelsea, with Turkey's Caglar Soyuncu arriving from Leicester and left-back Javi Galan moving from Celta Vigo.
Joao Felix, the club's record signing in 2019, is not viewed as part of coach Diego Simeone's plans following his return from an unsuccessful loan at Chelsea, and is expected to be offloaded. Real Sociedad, who qualified for the Champions League, have brought in Portugal forward Andre Silva on loan following the retirement of Spain great David Silva after a serious knee injury suffered during pre-season.
Villarreal, fifth last term, are set for a rebuild after losing Nicolas Jackson and Pau Torres to the Premier League, and Samuel Chukwueze to AC Milan. Granada are back in the top flight after securing promotion at the first attempt along with play-off winners Alaves, with Las Palmas returning after a five-year absence.