Welcome to My Favorite Scene ! In this series, IndieWire speaks to actors behind a few of our favorite television performances about their personal-best onscreen moment and how it came together. Jack Lowden is famously married to Saoirse Ronan , but asked about his favorite scene from “ Slow Horses ” Season 3 — he can’t stop complimenting his work wife. “Nothing fazes Roz in a take, nothing,” said Lowden of co-star and close friend Rosalind Eleazar .

“She’s just infallible and sort of bulletproof that woman. She’s amazing.” The actors, who play MI5 agents relegated to a detention-like posting in an underdog ensemble helmed by Gary Oldman, are headed into Season 4 of their seriocomic spy thriller for Apple TV+.

Streaming weekly as of September 4, “Slow Horses: Spook Street” (each season is subtitled after the books by Mick Herron they adapt) will once again see Lowden playing his the Emmy-nominated part of River Cartwright opposite Eleazar’s Louisa Guy. At the end of Season 3, “Slow Horses: Real Tigers” saw River and Louisa deep in the action, at one point squabbling over who would get to use the single handgun shared between them for much of the finale. The characters share a sibling-like dynamic that’s at times funny and often fraught.

Judging by the Reddit page, few if any “Slow Horses” fans want to see the duo’s unique connection turn romantic — but there’s an undeniably (platonic!) love to Lowden and Eleazar’s super-compelling o.