'Parks and Recreation' fans can't be happy about this: Rob Lowe and Rashida Jones, two of the most popular cast members on the NBC sitcom, will exit the show midway through the upcoming sixth season.

The departure of the pair was announced on Wednesday, July 31, with showrunner Mike Schur later issuing a statement that said in part, "We've been working on their storyline (on and off) for four seasons now, and heading into this year, with the two of them contemplating parenthood, it felt like a natural time to move them into the next phase."

Jones, who plays Ann Perkins, has been with the Amy Poehler-helmed show since it began, while Lowe's character Chris Trager joined the cast during season two. According to Schur, they'll get a "great Pawnee send-off" after the 13th episode of the new season (which premieres on Sept. 26).

Up next for Rob: a starring role in Nat Geo's upcoming 'Killing Kennedy' adaptation. (You'll also recall he recently had an epic, face-pulling role in HBO's Liberace bio, 'Behind the Candelabra.')

Jones, meanwhile, signed a two-year development deal with Warner Bros. Television back in January -- she'll write and produce comedy and drama projects for cable and network TV along with her 'Celeste & Jesse Forever' collaborator Will McCormack.