Eric Idle performed the voice of Merlin in Shrek the Third.

Shrek
Films
Shrek • Shrek 2 • Shrek the Third • Shrek Forever After
Characters Main Characters Shrek • Princess Fiona • Donkey • Dragon • Puss in Boots • Baby Ogres Other Characters Gingerbread Man • Magic Mirror • Pinocchio • Three Little Pigs • Three Blind Mice • Wolf Doris • King Harold • Queen Lillian • King Arthur • Merlin •Captain of Guards • Geppetto Villains Lord Farquaad • The Fairy Godmother • Prince Charming • Captain Hook • Rapunzel • Rumpelstiltskin
Cast Main Characters Mike Myers • Cameron Diaz • Eddie Murphy • Antonio Banderas Shrek Andrew Adamson • Cody Cameron • Chris Miller • Christopher Knights • Jim Cummings • John Lithgow • Conrad Vernon Shrek 2 Aron Warner • John Cleese • Rupert Everett • Kelly Asbury • Julie Andrews • Jennifer Saunders Shrek the third Eric Idle • Amy Poehler • Seth Rogen • Maya Rudolph • Justin Timberlake