British actress Diana Rigg, whose decades-long acting career spanned 1960s spy series "The Avengers," classical theater and "Game of Thrones," has died aged 82.

"It is with tremendous sadness that we announce that Dame Diana Rigg died peacefully early this morning," her agent Simon Beresford said in a statement. "She was at home with her family who have asked for privacy at this difficult time."

Her daughter Rachael Stirling said her mother died peacefully in her sleep after she was diagnosed with cancer in March. She said her mother "spent her last months joyfully reflecting on her extraordinary life, full of love, laughter and a deep pride in her profession."

"I will miss her beyond words," Stirling added.

Rigg, who won an Emmy award in 1997 for her performance as Mrs Danvers in "Rebecca" and a Tony award for playing the title character in "Medea," was also a Bond girl in 1969's "On Her Majesty's Secret Service."

More recently, Rigg found fame with a new generation of fans as Lady Olenna Tyrell in "Game of Thrones," but perhaps her most definitive role was secret agent Emma Peel in "The Avengers," in the classic series that was later adapted into the 1998 movie starring Ralph Fiennes and Uma Thurman.

Rigg was twice Emmy-nominated for her 1965-68 stint playing the catsuit-wearing, kickass spy opposite Patrick Macnee's bowler-hatted and besuited agent John Steed.

She won a special BAFTA (British Academy of Film and Television Arts) award in 2000, alongside Honor Blackman, Joanna Lumley and Linda Thorson, who all appeared in the series.

Rigg also won a BAFTA in 1990 for her part in TV series "Mother Love."