The Spaniard agreed to make his loan switch from the Barclays Premier League leaders to the San Siro a permanent one on December 27, but on Monday was announced as an Atleti player on loan until the summer of 2016.
The move, announced on the website of the Primera Division champions, sets the 30-year-old up for an emotional return to the Vicente Calderon.
He told Atletico’s official website clubatleticodemadrid.com: “I’m going to Atletico in the pursuit of my happiness.
“When I was a child, my dream was to play for Atletico. I achieved that and to come back now is another dream I get to accomplish again. I’ve been fine with other teams, but there isn’t one like Atleti.”
A lifelong fan of Los Rojiblancos, Torres did not celebrate when Chelsea scored against Atleti in the Champions League earlier this season and has made his love of the club well known.
“I was not a Liverpool fan or a Chelsea fan in Madrid,” he once said. “I was an Atletico fan. I still am. Maybe they’re the only badge I will kiss.”
Torres scored 91 goals in 244 appearances for Atleti after making his debut as a 17-year-old in 2001.
The Spain striker sent a message to the Atletico fans on Monday, saying: “Nobody can doubt how I’ll feel wearing that shirt again. Atleti fans always demand your all on the field and I guarantee that I will give them that and more.”
Liverpool signed him from the Spanish club in 2007 and, after thrilling Anfield for the best part of four years, he left for Chelsea in a #50million switch but the move started a steady decline in his personal fortunes.
Despite winning the FA Cup, Europa League and Champions League, he found goals hard to come by and a return of 45 goals in 172 games, while not prolific, is still not a true reflection of his struggles.
Just 20 of those goals were in the Premier League, scant return compared to the 65 the double European champion and one-time World Cup winner got for Liverpool.
He joined Milan at the start of the season but has continued to labour for goals, netting just once.
A statement from Atleti read: “Fernando Torres returns to Atletico Madrid after an agreement reached by our club with Milan for the international striker to play on loan for the remainder of the season and one more.
“The player will have a medical on January 5. He returns home, where he trained as a player and became one of our biggest stars.”