Susanna Thompson returning for 100th episode of 'Arrow'

Actress Susanna Thompson is officially returning as

Moira Queen

for 100th episode of "

Arrow

".

Details on how she is returning are being kept under wraps, reported Entertainment Weekly.

A series regular, Thompson, 58, left The

CW

show after season 2 when the Queen matriarch was killed by Deathstroke.

Even Deathstroke will return in the 100th episode, as revealed in a photo posted by Stephen Amell.

Katie Cassidy and Jamey Sheridan will also reprise their roles as Laurel Lance and Robert Queen, respectively, in the episode.

WATCH: Arrow - Susanna Thompson Talks About Playing Moira Queen