Peter Ustinov, the two-time Oscar-winning British character actor whose film roles ranged from Emperor Nero to Agatha Christie’s Belgian master detective Hercule Poirot, has died. He was 82.

Ustinov, a longtime international goodwill ambassador for UNICEF, died of heart failure Sunday night in a clinic in Genolier, Switzerland, near his longtime home in Bursins overlooking Lake Geneva.

In a stage and film career spanning more than 60 years, the versatile Ustinov earned international recog-nition as an actor, director, producer, playwright and novelist.

On screen, the portly actor was known for his genius in assuming different ethnic accents and personalities in many of the nearly 90 films in which he appeared. He won his supporting actor Oscars for the role of the gladiator-school owner in “Spartacus” (1960) and the part of a small-time British black marketeer in Turkey in “Topkapi” (1964).

James Agate, the London drama critic, once observed: “Ustinov is whipped by something which must be genius since it cannot be talent, for the first characteristic of talent is the taking of trouble, and I suspect that Ustinov never takes any.”

Ustinov won three Emmys for his television role as Samuel Johnson in “Dr. Johnson,” Socrates in “Barefoot in Athens” and an aged Jewish delicatessen owner in “A Storm in Summer.”

He won a Grammy for best recording for children for “Peter and the Wolf” (1959), which he narrated.

He also wrote, produced, directed and acted in the 1962 British sea adventure film “Billy Budd.”

UNICEF star

Offscreen, Ustinov was well-known for his volunteer work with UNICEF, the U.N. children’s fund.

Appointed a Goodwill Ambassador in 1968, his travels on behalf of UNICEF took him to China, Russia, Myanmar, Cambodia, Kenya, Egypt, Thailand and other countries. He also was host of scores of international television specials and benefit concerts for UNICEF.

“The children of the world have lost a true friend …,” UNICEF executive director Carol Bellamy said in a statement Monday. “Sir Peter had a magical way with children and an inimitable way of making their problems matter to people all over the world. He was one of UNICEF’s most effective and beloved partners, a man who exemplified the idea that one person can make a world of difference.”

After his 1978 debut as Poirot in the star-studded “Death on the Nile,” Ustinov played the immaculately dressed detective in “Evil Under the Sun” (1982) and “Appointment with Death” (1988), as well as in three TV movies.

The twice-divorced Ustinov, who was knighted by the Queen of England for his artistic and humanitarian efforts in 1990, is survived by his wife, Helene, whom he married in 1972; and his four children.