United Kingdom, Oct. 16 -- Michael J. Fox and Eric Stoltz have developed a "friendly correspondence" 40 years after Back To The Future.

The 64-year-old star replaced Eric, also 64, as Marty McFly in the iconic 1985 sci-fi blockbuster six weeks into production, and the pair hadn't spoken until Michael decided to send him a letter decades after the change.

As reported by Entertainment Weekly, he wrote in new memoir Future Boy: "Eric has maintained his silence on the subject for 40 years, so I was prepared for the likelihood that he'd prefer to keep it that way."

In the letter, he quipped: "If your answer is 'p*** off and leave me alone'. That works, too."

Instead, Eric sent back a "beautifully written reply", jokingly telling Michael to...