Hosted by Cat Deeley, the two-hour broadcast will feature the top eight, who will be joined by the "So You Think You Can Dance" All-Stars. Lady Gaga and Marshall will judge the contestants alongside series resident judges Nigel Lythgoe and Mary Murphy.
Lady Gaga will return the following night for a special live performance on the July 28 results show alongside dance group LXD.
"So You Think You Can Dance" has traveled across the country in search of dancers who represent the best in America. Contestants work with top choreographers and are then judged on multiple styles of dance.
Marshall was nominated for the Tony Award for Best Choreography for his work on Kiss of the Spider Woman, Damn Yankees, She Loves Me, Cabaret and Little Me. He was also nominated for Best Direction for Cabaret.
"So You Think You Can Dance" airs Wednesday and Thursday nights at 8 PM ET on Fox.