Joanna Lumley has joined the cast of Mistresses.

The acting legend will play the bossy mother of Katie (Sarah Parish) – who rocks her world when she turns up unannounced in search of a new life – in the forthcoming third series of the BBC One drama.

“I am thrilled to have been asked to join this talented cast for the finale of this hugely popular series,” Joanna said in a statement.

BBC Wales executive producer Bethan Jones said: “Joanna is an acting legend and we are thrilled that she has agreed to join the wonderful Mistresses cast.

“She’ll add her special touch to this already much loved series as it reaches its dramatic conclusion next year.”

This third series, which begins filming in Bristol in spring 2010, focuses on the enduring friendship of Katie, Siobhan (Orla Brady), Trudi (Sharon Small) and Jessica (Shelley Conn).