Nastasha (left) and Joely Richardson
Peter Kramer/AP; Scott Kirkland/INF
03/27/2009 at 08:00 AM EDT
Joely Richardson is immersing herself in her craft after the sudden death of her older sister, Natasha.
The actress, 44, said her final goodbyes
to her sister Sunday. On Thursday, she was back on the
London set of her latest project, a remake of The Day of the Triffids
, a rep for Richardson confirms to PEOPLE.
Filming is due to wrap up next month. Joely plays the lead female role of opposite Dougray Scott in the two-part sci-fi drama based on John Wyndham's novel.
The series also stars the Richardsons' mother, Oscar winner Vanessa Redgrave, who had already finished filming her role before the tragedy.
Richardson was given special leave from the set when news broke of her sister's skiing accident
in Canada. Two days later, Natasha's death