Allison Janney's hit TV comedy series Mom is set to end after the current season, following the departure of Anna Faris.

The U.S. show, which launched back in 2013, revolved around the dysfunctional relationship between Faris' character Christy Plunkett and her unconventional mother Bonnie, played by Janney.

It was one of the best-rated comedies on the CBS network, but it appears showrunners have decided to end the show after season eight comes to a close in May.

"For the past eight years, we've had the great honour to bring these wonderful characters to life, sharing their struggles and triumphs with millions of viewers every week," executive producers Chuck Lorre, Gemma Baker and Nick Bakay shared in a statement on Wednesday.

"We are forever grateful to our brilliant cast and guest stars, wonderful writers, and amazing crew for going on this journey with us."

Kelly Kahl, president of CBS Entertainment, thanked Janney for carrying the show after the shock departure of leading lady Faris, and said she was proud of the range of issues included on the show.

"Since its premiere, Mom has touched people's lives by sensitively tackling weighty yet relatable topics, with a perfect, deft touch. Mom redefined what a comedy can be, and we are proud to have been the network home to this wonderful series," she shared.

Faris surprised fans in September when she announced she would be leaving the show just days before production was due to begin on its eighth season. Her character's absence has been explained in a storyline about her attending law school.