11 March] 1887 – 27 September 1967) was a Russian aristocrat from the House of Yusupov who is best known for participating in the assassination of Grigori Rasputin and for marrying Princess Irina Alexandrovna, a niece of Emperor Nicholas II.

For the Yusupov name not to die out, his father (1856, Saint Petersburg – 1928, Rome, Italy) was granted the title and the surname of his wife, Princess Zinaida Yusupova, on 11 June 1885, a year after their marriage, but effective after the death of his father-in-law in 1891.

Yusupov made a quick exit by smashing a champagne bottle over the nightclub's power box to cause a temporary blackout and ran off into the winter's night.

[8] Yusupov was living on 14 King Edward Street, had a Russian cook, a French driver, an English valet, and a housekeeper, and spent much of his time partying.

He smoked hashish,[7] danced the tango, and became friendly with Luigi Franchetti, a piano player, and Jacques de Beistegui, who both moved in.

[10] The Yusupovs went on honeymoon to the Crimea, Italy, Egypt, Jerusalem, London, and Bad Kissingen in Germany, where his parents were staying.

The Kaiser refused to permit the Yusupov family to leave but offered them a choice of three country estates to live in for the duration of the war.

Felix's father appealed to the Spanish ambassador in Germany and won permission for them to return to Russia via neutral Denmark to the Grand Duchy of Finland and from there to Saint Petersburg.

[11][citation needed] The Yusupovs' only daughter, Princess Irina Felixovna Yusupova, nicknamed Bébé, was born on 21 March 1915.

[citation needed] Felix was able to avoid entering military service himself by taking advantage of a law exempting only sons from serving.

Irina's first cousin, Grand Duchess Olga, to whom she had been close when they were children, was disdainful of Felix: "Felix is a 'downright civilian,' dressed all in brown, walked to and fro about the room, searching in some bookcases with magazines and virtually doing nothing; an utterly unpleasant impression he makes – a man idling in such times," Olga wrote to Nicholas on 5 March 1915 after paying a visit to the Yusupovs.

"[15] These sessions stopped early January 1915 when, according to Maurice Paléologue, the most absurd stories were spread about Alexandra Feodorovna being the Starets' lover, Rasputin was also accused of espionage for Imperial Germany, and the tsarina was called nothing but "the German woman" (her birth nationality).

[17] In February 1916 Felix began studies at the elite Page Corps military academy and tried joining an Imperial Russian Army regiment in August.

The heavy losses by the Russian military gave rise to a lot of rumors that Yusupov’s family was involved in misprision of treason, according to Alexander Spiridovich: Sunday, June 13, 1915: There were also stormy demonstrations at the gates of the Convent of Martha-and-Mary, the abbess of which is the Grand Duchess Elizabeth Feodorovna, the Empress's sister and widow of the Grand Duke Sergei.

This charming woman, who spends her whole life in devotion and good works, has been smothered with insults, for the people of Moscow have long been convinced that she is a German spy ….

[21] Yusopov then asked Sergei Mikhailovich Sukhotin, a Preobrazhensky Regiment officer recovering from war injuries, who was also a friend of his mother.

[23] On 20 November, Felix visited Vladimir Purishkevich, who had delivered an angry anti-Rasputin speech in the Duma on the day before, and who quickly agreed to participate in the assassination.

[24] On the night of 29/30 December (NS) 1916, Felix, Dmitri, Vladimir Purishkevich, assistant Stanislas de Lazovert, and Sukhotin killed Rasputin in the Moika Palace under the pretense of a housewarming party.

Perhaps some women were invited but Yusupov did not mention their names; Radzinsky suggested Dimitri's step-sister Marianne Pistohlkors and film star Vera Karalli.

[28] Yusupov mentions in his unreliable memoirs, that he then offered Rasputin tea and petit fours laced with a large amount of potassium cyanide.

According to the diplomat, Maurice Paléologue—who in later years rewrote his diary—they discussed spirituality and occultism;[29] the antique dealer Albert Stopford wrote that politics was the issue.

On the empress's orders, a police investigation commenced and traces of blood were discovered on the steps to the back door of the Yusupov Palace.

Prince Felix attempted to explain the blood with a story that one of his favorite dogs was shot accidentally by Grand Duke Dmitri.

One of the British officers noted that Irina "appeared shy and retiring at first, but it was only necessary to take a little notice of her pretty, small daughter to break through her reserve and discover that she was also very charming and spoke fluent English.