McKellen's Lear rounds off the RSC's Complete Works season and is being staged in repertory with Nunn's production of The Seagull.
Performances of Chekhov's classic begin April 7 with McKellen alternating in the role of Sorin with actor William Gaunt.
Gaunt (credits include Humble Boy and The Cherry Orchard for the National) makes his RSC debut in the role-sharing production.
Both Shakespeare and Chekhov plays perform in repertory at the Courtyard until June 23, after which the productions embark on an international tour taking in Singapore, Australia, New Zealand and arriving in the U.S.A. on Sept. 6 at New York's Harvey Theatre.
The tour then moves on to the Guthrie Theatre, MN, beginning Oct. 5 and Los Angeles' Royce Hall beginning Oct. 19. The ensemble cast for both plays includes Frances Barber, Romola Garai and, for Lear only, Sylvester McCoy.
Garai, best known for such screen work as "Inside I'm Dancing" and "Vanity Fair," plays Cordelia in Lear and Nina in The Seagull. The plays represent her RSC debut, which is also true of her fellow rising star, drama student Richard Goulding, who plays Konstantin in The Seagull.
Barber was last seen in the West End in One Flew Over the Cuckoo's Nest with Christian Slater. Other credits include Cleopatra in Antony and Cleopatra and Aladdin, with McKellen's Widow Twanky. For her latest collaboration with McKellen, she plays Goneril in Lear and Arkadina in The Seagull.
McCoy, who last appeared with the RSC in the company's 2001 production of The Lion, the Witch and the Wardrobe, plays The Fool in Lear. He is best known for his television appearances as "Dr. Who."
Speaking about the two productions Nunn, who was the RSC's artistic director from 1968 - 1986 said, "For many years now I have been hoping to return to my theatrical roots in the RSC, and for even longer, I have been looking forward to the fulfilment of the vow Ian McKellen and I made that one day we would do King Lear together. Add to that the fact that we both believe in ensemble work playing in repertoire, and you have the background of this exciting plan to perform these two plays with the same cast in Stratford-upon-Avon."
The knighted Ian McKellen, last seen on Broadway in Dance of Death, won a Tony Award for his turn as Salieri in Amadeus. He also appeared in his autobiographical work A Knight Out at the Lyceum Theatre. The actor is also known for his film work in the "X-Men" and "The Lord of the Rings" trilogies, "The Da Vinci Code," "Gods and Monsters," "Bent" and "Six Degrees of Separation."
For more on King Lear and The Seagull, call (0)870 7845 0512.