Daniel Gideon Mazer is a British director, screenwriter, producer, and comedian. He is best known as the long-time writing and production partner of comedian Sacha Baron Cohen and worked with him on his three unorthodox characters Ali G, Borat, and Brüno. He also co-wrote and co-produced the films based on Baron Cohen's characters such as Ali G Indahouse, Borat, and Brüno.

Dirty Grandpa is a 2016 American buddy sports romantic sex comedy film about a lawyer who drives his grandfather to Florida during spring break. The film was directed by Dan Mazer and written by John Phillips. It stars Robert De Niro and Zac Efron in the leading roles, with Aubrey Plaza, Zoey Deutch, Julianne Hough and Dermot Mulroney in supporting roles. It was filmed on location in Atlanta from January 19 to May 9, 2015.