NEW YORK — Serious theater fans have a reason to suddenly freak out: Ian McKellen and Patrick Stewart will team up on Broadway this fall in two of the most iconic plays of the 20th century.

Stewart and McKellen will star in Harold Pinter’s “No Man’s Land” and Samuel Beckett’s “Waiting for Godot,” which will play in repertoire.

The production dates will be announced later.

Stewart and McKellen starred in a production of “Waiting for Godot” in London’s West End in 2009. Prior to Broadway, they’ll tackle “No Man’s Land” in an as-yet-unspecified out-of-town tryout.

Stewart, 72, and McKellen, 73, first worked together in 1977 in Tom Stoppard’s “Every Good Boy Deserves Favour.” They’ve also starred in the “X-Men” movie franchise as Professor Xavier and Magneto.

Now a thorny question: Who gets top billing on Broadway: McKellen or Stewart? After all, both actors have gotten knighthoods for their services to drama and the performing arts.

“For me there’s no question,” Stewart said. “Ian was a star actor while I was still working in regional theater. To be absolutely frank, I was in awe of him and his work long before I knew him.”