Nate Richard’s review published on Letterboxd:
Popstar: Never Stop Never Stopping gives fans of The Lonely Island exactly what they'd want. Melding their signature style of humor into this hilarious mockumentary. It might be low on story but what it does have is the laughs that come often and hit hard.
Andy Samberg is fantastic as Conner4real, a Bieber-style musician who's career goes in a downward spiral after his latest album flops. Fellow Lonely Island members Akiva Schaffer and Jorma Taccone are also great. Though Tim Meadows and Sarah Silverman unfortunately don't get much to do in the laughs department. Don't forget the seemingly endless supply of celebrity cameos ranging from Ringo Starr to Justin Timberlake to Bill Hader to Jimmy Fallon to more celebrities than you can think of.
It does suffer from some poor pacing as it's runtime is definitely felt and there's a few patches that don't exactly having any laughs.
Overall Popstar: Never Stop Never Stopping gave me everything I wanted from a Lonely Island movie and would definitely recommend it to any fan of them.