"They're great. We have really great chemistry," Diggs, 36, said of his castmates Thursday at the opening of the new club Runway in New York City.
The initial episode has "just finished" filming, he said, "and we're hoping people dig it."
ABC plans to test out the show with a "back-door pilot," an expanded two-hour episode of Grey's, Reuters reported in February. No air date for the episode has been set.
