The former France Under-21 international has joined the LaLiga leader for a fee of €1.5million until the end of the season, when Atletico will have the option to buy him outright for an initial €33.5m.

Atletico is said to have concentrated all efforts on Dembele after having a bid rejected for Napoli's Arkadiusz Milik, with Diego Costa's mutual contract termination at the end of December leaving space for another striker.

Dembele has long been linked with some of Europe's biggest clubs and will supplement Atletico's already formidable attacking options that include Luis Suarez and Joao Felix.

Algeria striker Slimani arrived at Lyon on Wednesday on an 18-month contract to bolster its forward line as it battles for the Ligue 1 title.

Dembele came through the ranks at Fulham after leaving Paris Saint-Germain as a teenager, and his form there secured him a move to Celtic.

He scored 26 league goals across two seasons in Scotland and won six trophies, before leaving for Lyon in a reported €22m deal in 2018.

He hit double figures for goals in each of his first two Ligue 1 campaigns, while his 24 in 46 across all competitions in 2019-20 made him comfortably Lyon's leading goalscorer with nine more than Memphis Depay, though the Dutchman missed a chunk of the season through injury.

However, 2020-2021 has been a tough one for Dembele, who scored just once in 16 league games for Lyon, with Depay, Karl Toko Ekambi and Tino Kadewere proving more dependable for Rudi Garcia.

While Dembele's shooting accuracy has only seen a slight dip this term from 52 per cent to 47.6, his conversion rate has slumped dramatically.

In the 2019-2020 Ligue 1 season, the striker converted 32 per cent of his shots attempted (excluding blocks), a figure only Mauro Icardi (37.5), Wissam Ben Yedder (35.3) and Kasper Dolberg (34.4) could better among players to record at least 30 shots.