The new episodes follow the success of a 2014 BAFTA-nominated one-off special which saw the foul-mouthed pensioner let loose on staff working in a council office.
Shane Allen, Controller, Comedy Commissioning, says: “Nan is one of the most iconic comedy characters of our time and it’s thrilling to welcome her back to BBC One.
“Catherine’s performance is as close to comic perfection as you can get.”