"Ant-Man" star Martin Donovan has joined "DC's Legends of Tomorrow" as Zaman Druce, Rip Hunter's mentor and fellow Time Master. He will appear in the fourth episode, "White Knights," as a guest star with the possibility to recur.

According to IGN, Druce is "a respected member of the time council who was Rip's first mentor at the Time Master Academy" and has a lot of experience mediating conflicts throughout history. However, when he is tasked with ending Hunter's quest to get Vandal Savage, death may be the only way to truly stop "the man he looked upon as a son."

In addition to a number of roles in television series like "Homeland," "Hannibal" and more, Donovan has appeared in many of Hal Hartley's films, including the indie film "Ned Rifle" alongside Aubrey Plaza.

Premiering this Thursday, "Legends of Tomorrow" stars Caity Lotz as White Canary, Brandon Routh as the Atom, Wentworth Miller as Leonard Snart/Captain Cold, Dominic Purcell as Mick Rory/Heat Wave, Victor Garber as Professor Martin Stein (one-half of Firestorm), Franz Drameh as Jefferson "Jax" Jackson (the other half of Firestorm), Ciara Renee as Hawkgirl and Arthur Darvill as time-traveler Rip Hunter.