Raikkonen -- nicknamed "the Iceman" -- is not expected to be cowed by Alonso's strong personality or his abilities on track.
Ferrari will hope their "fire and ice" combination will bring out the best in each other as it seeks to win its first team title since 2008.
Team principal Stefano Domenicali chose only to focus on Raikkonen's comeback Wednesday, saying: "I sense he is very happy to be returning to Maranello and very determined to tackle the work that awaits him in the best way possible."
Ferrari's late founder Enzo Ferrari had a reputation for encouraging rivalry between his drivers but Ferrari has preferred to adopt a policy of focusing on a lead driver since Michael Schumacher joined in 1996.
Silent but deadly
Raikkonen is as renowned for his reticence as he is for his pure speed -- the 33-year-old simply prefers to do his talking on the track.
But his occasional, pithy one-liners have earned him a legion of global fans.
His comment to Lotus on team radio as he raced to victory in Abu Dhabi last year ("Leave me alone, I know what I'm doing") was so popular it has appeared as a slogan on t-shirts and mugs.
Back in 2001, Raikkonen was fast tracked into F1 by Sauber after competing in a mere 23 races in motorsport's junior categories.
McLaren was the next team to recognize Raikkonen's natural talent, and snapped him up on a long-term deal in 2002.
The following season, Raikkonen took Schumacher down to the final race of the season in a thrilling championship but he would have to wait for the German to retire before finally getting his hands on an elusive world title.
Ferrari chose Raikkonen as Schumacher's replacement in 2007, hiring him for a reported $41 million.
He soon earned his corn, bringing the drivers' title back to Ferrari after seeing off Hamilton by a single point.
Ferrari has now returned to Raikkonen for a quick fix as the Scuderia desperately seeks to rein in the all-conquering Red Bull team.
Raikkonen, who turns 34 in October, will not be able to offer a long-term solution -- but Ferrari chiefs are gambling on the fact that given the right car he will deliver, and deliver quickly.