It's being described as "a family-centric comedy that revolves around a future pop star's unconventional upbringing and his awkward teenage years." The "unconventional upbringing" is mostly that he was raised by his mother and grandparents.
As for the "awkward teenage years," it sounds like the show will focus on his pre-fame life. But Justin's career was really starting to come together when he was 13 . . . so it's unclear if any of that will be brought in, or if the fictional Justin will just have a longer incubation period.
Justin won't star on the show . . . of course . . . but he will serve as an executive producer, along with his manager, Scooter Braun. A couple guys who worked on "Entourage" are also onboard, which makes sense.