Mark Alexander Knox (born April 15, 1970), better known as Flex Alexander or Flex, is an American actor, comedian and dancer. Born in Harlem, Alexander is the son of Alethia Knox and Robert Whitehead. As a teen, he began dancing in New York night-clubs earning the nickname "Flex" due to his acrobatic dance skills. After being discovered by DJ Spinderella, he began touring with rap trio Salt-n-Pepa's and remained with the dance troupe for three years. In addition to dancing, Alexander also choreographed for Mary J. Blige and Queen Latifah. In 1989, he made his stand-up comedy debut and eventually turned to acting, making his film debut in the 1992 film Juice. Alexander also was a regular cast member of the sketch comedy show, Uptown Comedy Club, from 1992-1994.

For more information press the link below:
https://en.wikipedia.org/wiki/Flex_Alexander