CREATE TABLE table_24725951_1 (directed_and_produced_by VARCHAR, celebrities VARCHAR)

List the director and producer when Nick Hewer and Saira Khan were starring.
SELECT directed_and_produced_by FROM table_24725951_1 WHERE celebrities = "Nick Hewer and Saira Khan"
SELECT "directed_and_produced_by" FROM "table_24725951_1" WHERE "Nick Hewer and Saira Khan" = "celebrities"