Sylvester Stallone is signing on to reprise his role as boxer Rocky Balboa and will direct the sixth installment of the long-running film series, titled simply "Rocky Balboa," from his own script.

The film will be co-produced and co-financed by MGM, Columbia Pictures and Revolution Studios and will be distributed by Columbia Pictures.

Stallone - who directed the second, third and fourth "Rocky" movies and who has written all five installments - has been trying to mount a sixth movie for years and has been spent time reworking a script. The latest version, which sources said is similar to tone and grit to the first two movies, persuaded the studios to negotiate a deal.

"In many ways, the screenplay really took me back to the original 'Rocky,' " Revolution Studios founder Joe Roth said in a statement. "As a past champion, Rocky Balboa is once again a regular guy who has to find himself and deal with real life. This film brings Rocky's story full circle."

In the new installment, Rocky, lonely and retired in Philadelphia, comes out of retirement, intending to fight a few low-profile local fights. He is approached to fight a match with reigning heavyweight champ Mason "The Line" Dixon, and soon his comeback sets off a media firestorm.

" 'Rocky Balboa' is about everybody who feels they want to participate in the race of life, rather than be a bystander," Stallone said in a statement. "You're never too old to climb a mountain, if that's your desire."

Shooting is scheduled to begin in December in Los Angeles and Philadelphia.

Stallone received Academy Award nominations for starring in and writing "Rocky," and the 1976 MGM film won an Oscar for best picture, best director and best editing. The movie grossed $117.3 million at the domestic boxoffice, making Stallone a star and creating one of cinema's most famous characters.

It also launched one of the most successful film series of all time; 1979's "Rocky II" grossed $85 million, while 1982's "Rocky III," which featured Mr. T, grossed $120.2 million. "Rocky IV," with Dolph Lundgren, released in 1985, made $125.4 million. By the decade's close, however, audiences seemed to have tired of the charac