United Kingdom, March 5 -- Nathan Fillion has teased a major "announcement" sparking rumours of Firefly revival.

The 54-year-old actor - who played Captain Malcolm Reynolds in the cult classic space Western show and feature film sequel Serenity - has got fans talking after sharing videos of him visiting former co-stars including Gina Torres (Zoe Washburne), Morena Baccarin (Inara Serra), Sean Maher (Simon Tam), and Summer Glau (River Tam).

In the videos on his Instagram, Nathan can be seen visiting the homes of his castmates and telling them: "It's time."

In one caption, he wrote: "Wait... time for what? What's it time for?"

In another, he added: "Wait. Doing what? What are we doing? What are we doing, you son of a b****?!"

Nathan no...