Stolen Moments (1920) is a silent film starring Marguerite Namara with Rudolph Valentino playing a villain, the last film in which he played one.
 It was released in December 1920, just a few months before Valentino was elevated to stardom by his performance in "The Four Horsemen of the Apocalypse" (released 6 March 1921).
 In fact, filming of "Stolen Moments" was expedited so that Valentino could make it to Hollywood before filming began on "The Four Horsemen of the Apocalypse".
Anthony John "Tony" Dexter (January 19, 1913 – March 27, 2001) was an American actor known for his striking resemblance to silent film hero Rudolph Valentino, whom he portrayed in the 1951 biographic "Valentino".
 Dexter sometimes used the pseudonym Walter Craig.
 He was known for portraying many real-life characters such as Captain John Smith, Captain William Kidd, Billy the Kid and Christopher Columbus.
Jean Acker (October 23, 1893 – August 16, 1978) was an American film actress with a career dating from the silent film era through the 1950s.
 She was perhaps best known as the estranged wife of silent film star Rudolph Valentino.
The Son of the Sheik is a 1926 American silent adventure/drama film directed by George Fitzmaurice and starring Rudolph Valentino and Vilma Bánky.
 The film is based on the 1925 romance novel of the same name by Edith Maude Hull, and is a sequel to the 1921 hit film "The Sheik", which also stars Rudolph Valentino.
 "The Son of the Sheik" is Valentino's final film and was released nearly two weeks after his death from peritonitis at the age of 31.
Rudolph Valentino (1895–1926) was an Italian-born actor in the era of silent films.
 He emigrated to the United States in 1913 and took a string of temporary menial jobs before becoming a film extra in 1914.
 He appeared in several films until 1921—many of which are now lost.
 That year he got his major break when he appeared in the role of Julio in "The Four Horsemen of the Apocalypse".
 According to Valentino's biographer, Noel Botham, the film was "hailed ... [as] a masterpiece and Valentino as a star"; the film grossed $4.5 million at the North American box office.
When Love Grows Cold is a lost 1926 silent film drama directed by Harry O. Hoyt, and starring Clive Brook and Natacha Rambova in her only screen starring performance.
 Rambova was chiefly famous for being the wife of Rudolph Valentino.
 The film was originally titled "Do Clothes Make the Woman?"
 But in view of Valentino's recent divorce from Rambova, the distributor took the opportunity to bill her as 'Mrs Valentino' and changed the title to "When Love Grows Cold".
 She was mortally offended and never worked in film again.
The Ladder of Lies is a lost 1920 American drama silent film directed by Tom Forman and written by Edith M. Kennedy and Harold Vickers.
 The film stars Ethel Clayton, Clyde Fillmore, Jean Acker, Irving Cummings, Charles Meredith and Ruth Ashby.
 The film was released on July 11, 1920, by Paramount Pictures.
Vilma Bánky (9 January 1901 – 18 March 1991) was a Hungarian-born American silent film actress, although the early part of her acting career began in Budapest, spreading to France, Austria, and Germany.
 Bánky was best known for her roles in "The Eagle" and "The Son of the Sheik" with Rudolph Valentino and several romantic teamings with Ronald Colman.
Camille is a 1921 American silent drama film starring Alla Nazimova as Marguerite and Rudolph Valentino as her lover, Armand.
 It is based on the play adaptation "La Dame aux Camélias" ("The Lady of the Camellias") by Alexandre Dumas, "fils", which was first published in French as a novel in 1848 and as a play in 1852.
 "Camille" is one of numerous screen adaptations of Dumas, "fils"' story.
 The film was set in 1920s Paris, whereas the original version took place in Paris in the 1840s.
 It had lavish Art Deco sets and Rudolph Valentino later married the film's art director, Natacha Rambova.
John Gilbert (born John Cecil Pringle; July 10, 1899 – January 9, 1936) was an American actor, screenwriter and director.
 He rose to fame during the silent film era and became a popular leading man known as "The Great Lover".
 At the height of his career, Gilbert rivaled Rudolph Valentino, another silent film era leading man, as a box office draw.

Question: The Ladder of Lies stars what american film actress best known as the estranged wife of silent film star Rudolph Valentino
Answer: Jean Acker