Mission: Impossible fans are convinced a dead character returns in the final few seconds of Final Reckoning – without anyone noticing until now

Mission: Impossible – The Final Reckoning made good on its promise of an endgame with a NOC list's worth of callbacks, references to the series' storied history, and returning faces.

Which makes one spy all the more noticeable by their absence. Except, if you believe this wild new Final Reckoning theory, they did show up in The Final Reckoning's closing seconds – without anyone realizing.

Spoilers for Mission: Impossible – The Final Reckoning ending follow.

As Ethan Hunt returns to London after the Entity is trapped and nuclear catastrophe averted, several members of his team pop out of the crowd in Trafalgar Square. They include Benji (Simon Pegg), Degas (Greg Tarzan Davis), Paris (Pom Klementieff), and Grace (Hayley Atwell), who gives Ethan the Entity for safe keeping.

But… that's it. No surprise reveal from the shadows or mask pull here. Yet, when Ethan walks away, pay particular attention to the woman walking next to him next time you're in the cinema for a Final Reckoning rewatch.

Eagle-eyed fans are convinced that's actually Rebecca Ferguson's Ilsa Faust, the co-star of Rogue Nation and Fallout. Ilsa was later killed off in unceremonious fashion during Dead Reckoning by Gabriel (Esai Morales) in Venice, leaving audiences wrongfooted after the seventh Mission: Impossible movie already dropped a Ilsa death fakeout during its first act.

Since then, fans have been hoping to see Ethan and Ilsa reunite. Now, we might have our wish.

If you look even closer, you can spot director Christopher McQuarrie over Ethan's right shoulder in the final scene – meaning there could be secrets upon secrets in Final Reckoning's last frame.

For more, check out our ranking of the best Mission: Impossible movies and the major Mission: Impossible – The Final Reckoning Easter eggs.