Addison will join host Dara O'Briain and regulars Hugh Dennis and Andy Parsons when the new series launches in September.
The stand-up, who has appeared on the show numerous times before, will be a replacement for Frankie Boyle, who exited the programme in 2009, and Russell Howard.
"Chris is a great signing for the autumn run. With party conferences and major sporting events coming up, I imagine he'll be given a roving role as he has the ability to supply quality ammunition for Dara in the centre as well as the confidence to go it alone," said a show rep.
"With appearances from the likes of Micky Flanagan, Milton Jones, Ed Byrne, Stewart Francis, Miles Jupp and Ava Vidal in the pipeline, it looks like Mock the Week really will be the panel show to watch this season."
Mock The Week returns on Thursday, September 8 at 10pm on BBC Two.
Watch a clip of Chris Addison in Live At The Apollo below: