Question: Ursula Reith is best known for her role as Mrs. Gloop in a 1971 American musical fantasy film that was directed by Mel Stuart, and starred who?
Context: Wattstax was a benefit concert organized by Stax Records to commemorate the seventh anniversary of the 1965 riots in the African-American community of Watts, Los Angeles.  The concert took place at the Los Angeles Memorial Coliseum on August 20, 1972.  The concert's performers included all of Stax's prominent artists at the time.  The genres of the songs performed included soul, gospel, R&B, blues, funk, and jazz.  Months after the festival, Stax released a double LP of the concert's highlights titled "Wattstax: The Living Word".  The concert was filmed by David L. Wolper's film crew and was made into the 1973 film titled, "Wattstax".  The film was directed by Mel Stuart and nominated for a Golden Globe award for Best Documentary Film in 1974. Ursula Reit (March 5, 1914 – November 9, 1998) also Ursula Reith, was a German television and movie actress, best known for her role as Mrs. Gloop in "Willy Wonka & the Chocolate Factory" (1971).  Most of her roles were on German television between 1965 and 1992, when she retired.  She was born in Wuppertal in 1914 and died in 1998 from natural causes. Milton "Mel" Stewart (September 19, 1929 – February 24, 2002) was an American character actor, television director, and musician who appeared in numerous films and television shows from the 1960s to the 1990s.  He is best known for playing Henry Jefferson on the popular television series "All in the Family" and for playing section chief Billy Melrose on the television series "Scarecrow and Mrs. King".  Stewart is sometimes credited as Melvin Stewart or Mel Stuart. Four Days in November is a 1964 American documentary film directed by Mel Stuart about the assassination of John F. Kennedy.  It was nominated for an Academy Award for Best Documentary Feature. Santa and the Ice Cream Bunny is a 1972 American musical fantasy film written, composed, shot, edited, and directed by R. Winer to frame Barry Mahon's Childhood Productions films for a Christmas release.  The threadbare plot concerns Santa Claus's attempts to free his sleigh from the sands of a Florida beach, assisted by local children. 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. If It's Tuesday, This Must Be Belgium is a 1969 DeLuxe Color romantic comedy film made by Wolper Pictures and released by United Artists.  It was directed by Mel Stuart, filmed on location throughout Europe, and features many cameo appearances from various stars.  The film starred Suzanne Pleshette, Ian McShane, Mildred Natwick, Murray Hamilton, Sandy Baron, Michael Constantine, Norman Fell, Peggy Cass, Marty Ingels, Pamela Britton, and Reva Rose. Into the Woods is a 2014 American musical fantasy film directed by Rob Marshall, and adapted to the screen by James Lapine from his and Stephen Sondheim's Broadway musical of the same name.  A Walt Disney Pictures production, it features an ensemble cast that includes Meryl Streep, Emily Blunt, James Corden, Anna Kendrick, Chris Pine, Tracey Ullman, Christine Baranski, Lilla Crawford, Daniel Huttlestone, MacKenzie Mauzy, Billy Magnussen, and Johnny Depp.  Inspired by the Grimm Brothers' fairy tales of "Little Red Riding Hood", "Cinderella", "Jack and the Beanstalk", and "Rapunzel", the film is a fantasy genre centered on a childless couple, who set out to end a curse placed on them by a vengeful witch.  Ultimately, the characters are forced to rectify the consequences of their actions. One Is a Lonely Number (also known as Two Is a Happy Number) is a 1972 American drama film directed by Mel Stuart and starring Trish Van Devere, Janet Leigh and Melvyn Douglas.  The screenplay, based upon the short story "The Good Humor Man" by Rebecca Morris, was written by David Seltzer. Mary Poppins Returns (also known as Mary Poppins 2) is an upcoming American musical fantasy film directed by Rob Marshall and written by David Magee.  It is the sequel to the 1964 film "Mary Poppins".  The film stars Emily Blunt, Lin-Manuel Miranda, Ben Whishaw, Emily Mortimer, Pixie Davies, Joel Dawson, Nathanael Saleh, Julie Walters, Colin Firth, Dick Van Dyke and Meryl Streep.  Set 25 years after the 1964 film, it will feature Mary Poppins, the former nanny of Jane and Michael Banks, re-visiting them after a family tragedy.  The film is scheduled for release on December 25, 2018, giving it one of the longest gaps between film sequels in history.
Answer: Gene Wilder