Season 4 premiered on M-Net Series on Tuesday 19 August 2008, at 19h00. Results shows were on Wednesdays at 19h00.
The season was won by Joshua Allen.
In Season Four, producers again travel across America in search of dancers who represent the rhythm of America. Those who spark the judges' interest during auditions will be invited to call-backs, where they will work with top choreographers.
During the call-back week, the judges choose the Top 20 dancers who will continue in the competition.
In the performance round, the 20 finalists dance for America's votes, and each week the six contestants comprising the bottom three couples are given a chance to perform solo routines to encourage viewers to keep them on the show.
Then the judges decide which dancers stay in the competition and which two are eliminated.
Once the series is down to the Top 10 finalists, it's solely up to America to decide who remains in the competition. Following the performance shows, viewers can vote for their favourite couples. The live results shows reveal who keeps dancing and who goes home.
The first season of the show was hosted by Lauren Sanchez. Since Season 2 it has been hosted by British presenter Cat Deeley.
After travelling around the country looking for the best dancers, producers invite 500 of the most talented to attend casting sessions in major cities across the nation.
At the casting sessions, each dancer must perform their own routine in front of a panel of judges, who then decide immediately who is good enough to continue.
Those chosen to stay work on a routine as a group, and after a further round of eliminations followed by a choreographed routine with a partner, the final 50 are selected to move on to the Dance Boot Camp.
At the Dance Boot Camp, each of the dancers is put through their paces by 5 choreographers, who take them through a variety of dance styles, from Hip Hop, to the Flamenco.
At the end of the camp, the group is immediately cut down, 20 of whom will be chosen to move forward to the studio shows after one-to-one interviews with the choreographers. This group is then cut down to a final 10.
Each studio show is structured the same way. As contestants are eliminated the remaining participants are randomly paired together, and the dances they need to perform the following week are drawn from a hat.
We follow each couple as they learn their routine by a top choreographer, before performing that routine in front of the panel of choreographers, and a live studio audience.
Once all the couples have performed, the panel identify the 3 weakest couples (or in later shows, 2 weakest couples) to go up for elimination by the public who vote for their favourites to stay.
Each dancer has an opportunity to encourage voters to keep them in the competition by dancing a solo routine for 45 seconds immediately before the phone lines are opened.
Each week, one guy and one girl is eliminated until only 4 dancers remain.
After performing for the last time, all 4 dancers are put to the public vote and it is the public who decide the final winner.
Dance styles featured on the show include jazz, contemporary, pop, modern, American jive, swing, disco, hip hop, krumping, paso doble, quickstep, lyrical, Broadway, Viennese waltz, smooth waltz, Argentine tango, mambo, cha cha, Cuban rumba, and salsa.
There are three judges on each show, one of whom is always producer Nigel Lythgoe. The other two judges are a rotation of professional dancers and choreographers.