Morata was on Atletico's books as a youngster and even acted as a ball boy for the club, but it was across the capital at Madrid where he broke through as a professional footballer.
After making a strong start at Stamford Bridge, a back injury contributed to Morata subsequently struggling at Chelsea and he slipped down the pecking order after last week's arrival of Gonzalo Higuain on loan from Juve.
Morata joined Atletico on an 18-month loan deal on Monday to complete his return to La Liga, where he won titles with Madrid in 2011-12 and 2016-17.
Atletico are in the hunt for this year's La Liga crown, with Diego Simeone's side five points back from champions Barcelona, and Morata will add to their attacking options with Diego Costa recovering from foot surgery and Nikola Kalinic having only scored twice in the league this term.
And Morata could not be happier to be given a fresh start in his home city, with his Atletico debut potentially coming at Real Betis on Sunday.
"In my career, it is a dream come true," Morata told Atletico's club website.
"When I was young I saw all the Atletico legends and the other players of La Liga.
"It's very important for me and it means a lot because I always wanted to play for Atletico Madrid - it's a very special day for me. I know Atletico: what it means, this club, this name. I already know the club inside.
"I know what I need to do here to have success and I think I'm in the right place to make another step in my life in a very important step in my career. I know a lot of team-mates and I know the club and I'm ready to fight and to play."