Raikkonen, the 2007 F1 world champion, signed a two-year agreement with LRGP. The 32-year-old Finn has spent the past two seasons competing in the World Rally Championship. This year, he competed in two NASCAR races -- one in the Nationwide Series and the other in the Camping World Truck Series.
"I'm delighted to be coming back to Formula One after a two-year break, and I'm grateful to Lotus Renault GP for offering me this opportunity," Raikkonen said in a team statement. "My time in the World Rally Championship has been a useful stage in my career as a driver, but I can't deny the fact that my hunger for F1 has recently become overwhelming.
"It was an easy choice to return with Lotus Renault GP, as I have been impressed by the scope of the team's ambition. Now I'm looking forward to playing an important role in pushing the team to the very front of the grid."
Raikkonen has accumulated 18 wins, 62 podiums and 16 pole positions in F1. He made his debut in the sport with Sauber in 2001. He then drove for McLaren from 2002-06 before his tenure with Ferrari from 2007-09.
Despite having one year left on his contract with Ferrari, he departed the Italian team at the end of the '09 season to make way for Fernando Alonso.
Raikkonen joins LRGP after the team finished fifth in the 2011 F1 constructors' championship.
"All year long, we kept saying that our team was at the start of a brand new cycle," LRGP Chairman Gerald Lopez said. "Backstage, we've been working hard to build the foundations of a successful structure and to ensure that we would soon be able to fight at the highest level. Kimi's decision to come back to Formula One with us is the first step of several announcements which should turn us into an even more serious contender in the future."
The team will be renamed Lotus next season.