Question: Which american dancer was annouced to be on "Dancing with the Stars" on September 1?
Context: Elvera Sanchez (September 1, 1905 – September 2, 2000) was an American dancer and the mother of Sammy Davis Jr. Julianne Alexandra Hough ( ; born July 20, 1988) is an American dancer, singer, and actress.  She is a two-time professional champion of ABC's "Dancing with the Stars".  She was nominated for a Creative Arts Primetime Emmy in 2007 for Outstanding Choreography in season five of the show.  Her first leading acting role was in the 2011 film remake of "Footloose".  In September 2014, Hough joined "Dancing with the Stars" as a permanent fourth judge.  Along with her brother Derek Hough (who is a six-time winner of the dancing show) and Tessandra Chavez, she won the Primetime Emmy Award for Outstanding Choreography in 2015.  In 2016, she played Sandy in the live Fox television production of "". Lacey Mae Schwimmer (born June 28, 1988) is an American ballroom dancer and singer.  She is best known as a fourth place finalist of the third season of "So You Think You Can Dance".  She is the daughter of noted dancer Buddy Schwimmer, as well as the cousin of Heidi Groskreutz, who placed fourth on the second season of "So You Think You Can Dance" and younger sister of Benji Schwimmer, the winner of the show's second season.  She participated in the seventh season of "Dancing with the Stars" as a professional dancer paired with Lance Bass of 'N Sync, in the eighth season of the show paired with "Jackass" star Steve-O and in the ninth season paired with actor and Iron Chef America host Mark Dacascos.  Schwimmer returned to "Dancing with the Stars" for its eleventh season and she was partnered with Disney Channel star Kyle Massey and in the 12th season, paired with radio host Mike Catherwood.  In the thirteenth season, she was paired with transgender activist Chaz Bono.  Schwimmer did not return for season 14 of "Dancing With The Stars'. Christopher "Lil' C" Toler (born 1983) is an American dancer and choreographer best known for his choreography and judging on the TV show "So You Think You Can Dance" and for his appearance in the 2005 krumping documentary "Rize".  Since appearing in the film he has danced for several musical artists including Missy Elliott, Fall Out Boy, and Madonna, and was cast as a featured dancer in the 2007 art exhibit "Slow Dancing".  He continues to serve as a guest judge on "So You Think You Can Dance". Mark Alexander Ballas Jr. (born May 24, 1986) is an American dancer, choreographer, singer-songwriter, musician, and actor. Doraldina, (1888–1936) was an American dancer and one of the Metro Pictures film stars.  Though given a splendid opportunity to display her histrionic talents as an actress, would, nevertheless, retain in her pictures the familiar Hawaiian setting with which her legion of admirers have come to associate her.  Beginning her career as a manicurist in a San Francisco hotel, Doraldina's rise to fame and stardom came as a fitting climax to a career during which she put forth every effort to please a discriminating public.  Studying the dancing art first in New York City, and then in Barcelona, Spain, she returned to New York where her career a dancer, actress, and screen star made of her a national figure.  Her first Metro production was "Passion Fruit" (1921). Eleanor Torrey Powell (November 21, 1912 – February 11, 1982) was an American dancer and actress.  Best remembered for her solo tap numbers in musical films in the 1930s and 1940s, Powell began studying ballet aged six and began dancing at nightclubs in Atlantic City before she was a teenager.  From the age of sixteen, she began studying tap and started appearing in musical revues on Broadway, before making her Hollywood debut as a featured dancer in the movie George White's Scandals (1935). Izabela Hannah is a Polish-born British ballroom and Latin American dancer.  Born in Szczecin, Poland, Hannah began dancing jazz and ballet at the age of 9, and started ballroom and Latin American dancing as a teenager.  During her competitive career she won international titles in Europe and the United States, winning the Polish Amateur Ballroom Championships in 2001 and again in 2002. Season eleven of "Dancing with the Stars" premiered on September 20, 2010.  The cast was announced during the August 30 episode of "Bachelor Pad" during a live press conference that included a Q&A session with host Tom Bergeron and co-host Brooke Burke and the new cast.  There are twelve celebrity cast members this season.  The pairs were announced on September 1 (however, Bristol Palin and Mark Ballas were announced as being a couple the day before by way of a "Good Morning America" interview). Carrie Ann Inaba (born January 5, 1968) is an American dancer, choreographer, television dance competition judge, actress, game show host, and singer.  She is best known for her work on ABC TV's "Dancing with the Stars".
Answer: Mark Ballas