Question: Which American actor, screenwriter, director, producer, singer-songwriter and author sang this song from the 1971 movie "Willy Wonka & the Chocolate Factory" that was written by British composers Leslie Bricusse and Anthony Newley?

Context paragraphs:
The Candy Man: "The Candy Man" (or alternatively, "The Candy Man Can") is a song which originally appeared in the 1971 film "Willy Wonka & the Chocolate Factory".  It was written by Leslie Bricusse and Anthony Newley specifically for the film.  Although the original book by Roald Dahl ("Charlie and the Chocolate Factory") contains lyrics adapted for other songs in the film, the lyrics to "The Candy Man" do not appear in the book.  The soundtrack version of the song was sung by Aubrey Woods, who played Bill the candy store owner in the film.

Pure Imagination: "Pure Imagination" is a song from the 1971 movie "Willy Wonka & the Chocolate Factory".  It was written by British composers Leslie Bricusse and Anthony Newley specifically for the movie.  It was sung by Gene Wilder (Willy Wonka).  The intro of the song, which also is the musical code for entering the Chocolate Room played by Willy Wonka, is the introduction of Wolfgang Amadeus Mozart's "Marriage of Figaro".

What Kind of Fool Am I?: "What Kind of Fool Am I?"  is a popular song written by Leslie Bricusse and Anthony Newley and published in 1962.  It was introduced by Anthony Newley in the musical "Stop The World - I Want To Get Off".  It comes at the end of Act Two to close the show.  Bricusse and Newley received the 1961 Ivor Novello award for Best Song Musically and Lyrically, and the 1963 Grammy Award for Song of the Year, becoming the first Britons to do so.

Willy Wonka &amp; the Chocolate Factory: Willy Wonka & the Chocolate Factory is a 1971 American musical fantasy film directed by Mel Stuart, and starring Gene Wilder as Willy Wonka.  It is an adaptation of the 1964 novel "Charlie and the Chocolate Factory" by Roald Dahl.  Dahl was credited with writing the film's screenplay; however, David Seltzer, who went uncredited in the film, was brought in to re-work Dahl's screenplay against his wishes, making major changes to the ending and adding musical numbers.  These changes and other decisions made by the director led Dahl to disown the film.

The Willy Wonka Candy Company: The Willy Wonka Candy Company is a British brand of confectionery owned and licensed by Swiss corporation Nestlé.  The Wonka brand's inception comes from materials licensed from British author Roald Dahl.  His classic children's novel, "Charlie and the Chocolate Factory", and its film adaptations are the source of both the packaging and the marketing styles of the Wonka brand.  The brand was launched in 1971, coinciding with the release of the novel's first film adaptation.  In 1988 the Willy Wonka Candy Company brand – then owned by Sunmark Corporation – was acquired by Nestlé.  Nestlé sells sweets and chocolate under the Willy Wonka brand name in the United States, Canada, the United Kingdom, the Republic of Ireland, Australia, New Zealand, Japan, South Africa, Mexico, Colombia, Brazil, Argentina, Costa Rica, Panama, Dominican Republic and the Middle East.  In mid-2015 the Willy Wonka brand name was dropped by Nestlé, in favour of special "throwback" packaging.  Candies previously made by the Willy Wonka brand are now under the Nestlé brand naming, excluding the Wonka brand name on the top left corner.

Charlie and the Chocolate Factory (film): Charlie and the Chocolate Factory is a 2005 musical fantasy film directed by Tim Burton and written by John August, based on the 1964 British novel of the same name by Roald Dahl.  The film stars Johnny Depp as Willy Wonka and Freddie Highmore as Charlie Bucket.  The storyline follows Charlie, who wins a contest and is along with four other contest winners, subsequently led by Wonka on a tour of his chocolate factory, the most magnificent in the world.

Gene Wilder: Jerome Silberman (June 11, 1933 – August 29, 2016), known professionally as Gene Wilder, was an American actor, screenwriter, director, producer, singer-songwriter and author.

Anthony Newley: Anthony Newley (24 September 1931 – 14 April 1999) was an English actor, singer and songwriter.  Newley achieved success as a performer in such diverse fields as rock and roll and stage and screen acting.  As a recording artist he enjoyed a dozen Top 40 entries on the UK Singles Chart between 1959 and 1962, including two number one hits.  With songwriting partner Leslie Bricusse, Newley penned "Feeling Good", which was popularised by Nina Simone and covered by many other popular artists; as well as the title song of 1964 film "Goldfinger" (along with John Barry).  Bricusse and Newley received an Academy Award nomination for the film score of "Willy Wonka & the Chocolate Factory" (1971).

Wonka Bar: The Wonka Bar is both a fictional candy bar, introduced as a key story point in the 1964 novel "Charlie and the Chocolate Factory" by Roald Dahl, and a type of consumer product candy bar inspired by the fictional confection.  Wonka Bars appear in both film adaptations of the novel, "Willy Wonka & the Chocolate Factory" (1971) and "Charlie and the Chocolate Factory" (2005), and the play "Charlie and the Chocolate Factory the Musical" (2013) each with different packaging.

Roald Dahl's Willy Wonka (musical): Roald Dahl's Willy Wonka is a musical that combines elements of both Roald Dahl's book "Charlie and the Chocolate Factory" and of the 1971 movie "Willy Wonka & the Chocolate Factory" with newly created material.  The musical has several versions: the original version which premiered in 2004, the Junior version, the Kids version, and the Theatre for Young Audiences version.  All are owned by Music Theatre International, the company that owns the Willy Wonka license.

Supporting paragraphs: Pure Imagination Gene Wilder
Answer: Gene Wilder