CREATE TABLE table_27976 ("#" FLOAT, "Airdate" TEXT, "No. of couples" FLOAT, "First couple" TEXT, "Second couple" TEXT, "Third couple" TEXT, "Fourth couple" TEXT, "Viewers  ( millions ) " TEXT, "ITV1 weekly ranking" FLOAT)

Who was the first couple in the episode having a fourth couple of Sammy and Nat?
SELECT "First couple" FROM table_27976 WHERE "Fourth couple" = 'Sammy and Nat'
SELECT "First couple" FROM "table_27976" WHERE "Fourth couple" = 'Sammy and Nat'