Jan 4 (Reuters) - National Football League (NFL) Hall of Famer Joe Montana has avoided the documentary spotlight for decades but is letting his guard down this week, as a new series on the quarterback"s life and career debuts. From Michael Jordan"s 2020 juggernaut "The Last Dance" to the athlete memoirs that fill bookstore shelves, there is no shortage of sports "tell all" stories available - or voracious fans ready to eat them up. But the man who epitomized "Joe Cool" over 16 seasons in the NFL and refused every prior attempt to document his life in film, has relented with "Joe Montana: Cool Under Pressure," a six-part documentary that premieres on Thursday on the Peacock streaming service. "It"s always been one of those things, "Do I really want to do this?"" the three-time Super Bowl MVP told Reuters. "I was always pretty private about a lot of the things... it took a lot of convincing." The project"s premiere coincides with the 40th anniversary of "The Catch," the blockbuster pass to Dwight Clark to win the NFC Championship and set in motion the Niners dynasty that would result in four Super Bowl titles for Montana. But revisiting the footage wasn"t easy: Clark died in 2018 from amyotrophic lateral sclerosis, commonly known as ALS or "Lou Gehrig"s disease," which the late receiver suspected was caused from head trauma related to playing football. Former Superbowl champion quarterback Joe Montana, who played for the National Football League"s San Francisco 49ers and Kansas City Chiefs, poses during an interview in Toronto, Ontario, Canada January 22, 2019. Picture taken January 22, 2019. REUTERS/Chris Helgren Former Superbowl champion quarterback Joe Montana, who played for the National Football League"s San Francisco 49ers and Kansas City Chiefs, poses during an interview in Toronto, Ontario, Canada January 22, 2019. Picture taken January 22, 2019. REUTERS/Chris Helgren "It"s just hard when you when you see some of the film, a lot of the guys in there that are involved in the teams are gone and way too early, way too young," said Montana, a two-time league MVP. "You feel fortunate that, you know, I made it through so far without a lot of those things that guys are suffering from also." Football exacted a brutal toll on his body, of course, needing more than 20 surgeries but leaving his mind intact after a demanding career in a sport where he sees little chance of eliminating entirely the risk of head injury. "It"s really hard when what causes (injury) was when the brain moves and hits inside your skull. So how do you stop that?" said Montana. He credits the league with making strides to reduce head injuries, after it expanded its rules on helmet-to-helmet contact in 2018, but sees eliminating head injuries entirely as an enormous hurdle. "No matter how good the helmet is, you"re still moving forward and something stopping you. So inside your brain, it"s still moving," he added. "Until they can figure that out, I think we"ll always have a problem."