New Delhi, July 13 -- NEW YORK - The casting lineup Ryan Murphy assembled for American Horror Story Season 13, an all-star Coven reunion designed to function less like a new installment than a franchise event, has its first confirmed absence. Ariana Grande has stepped away from the FX anthology's thirteenth season due to a scheduling conflict with her Eternal Sunshine concert tour, a clash between two parallel careers that had, until now, seemed destined to overlap productively.

the Eternal Sunshine tour, which runs through August 23 in London, overlaps with production currently underway in New York City. With AHS Season 13 set to premiere September 24, barely five weeks after her final concert date, the window for filming simply could n...