Hugo Weaving breaks down that shocking Slow Horses season 4 finale reveal and explains why he didn't approach his character as a villain

Warning: the following features spoilers for the Slow Horses season 4 finale.

Unlike previous seasons, the fourth entry in hit Apple show Slow Horses took a more personal approach, with an intimate story centered on the Cartwright family, namely Jack Lowden's protagonist River. We follow the MI5 reject as he encounters Hugo Weaving's menacing Frank Harkness, a character our Slow Horses season 4 review says sends chills down the spine.

The pair's connection was a mystery until the season finale, where in the opening scene River greets Frank with "hello Dad" - cue our jaws dropping. Weaving agrees that the grand reveal is done brilliantly, telling GamesRadar+ that even though he knew his character's true identity before reading the script, he still found the twist to be thrilling. 

As he reveals: "I think it's tremendous. Slow Horse is brilliant at those pre-credit scenes and final ones too, the hooks to the next episodes are always so exciting. The pre-credit scene in the finale ends with that 'hello Dad' which is just so fantastic. You sort of knew that River had seen that image at the chateau on the wall and it meant something to him, but we didn't know why it was significant. So that reveal, it's great."

During their confrontation, River questions Harkness, who we know has fathered multiple children throughout the years separating them from their mothers at a young age, to train them up as mercenaries for his criminal business. In return, Harkness does something surprising, offering River a job, a chance to join his empire.

For Weaving though, this fits the outrageous nature of his character, as he explains: "It's a preposterous offer but Frank is a preposterous character. River realizes the man he's been tracking down is his own father and he's the one actually who's been caught. Then for that father to seemingly want to offer him a job, saying if he doesn't accept it he will kill him, it's just preposterous. He's a wonderful character so intelligent, calm, charming, and ruthless. He has a wonderful complexity and I like him, he makes me laugh. I don't think I'd like the man but I enjoy playing Frank."

Weaving goes on to reveal that when approaching his character he didn't see him as a villain, even though he is certainly a cruel antagonist this season. He explains that by not thinking of Frank as a villain, he could understand the character more: "I was at pains to make sure he isn't two-dimensional, I don't think he is at all but there is a danger there. You want a villain, which is a word I use occasionally as I don't really like to, but I do understand that Frank is a villain, looking from the outside he's the person they are chasing and the one creating the trouble."

Weaving continues, concluding: "But you want him to be real so I was trying to find as much humanity as I could in Frank, understanding where he has come from, what he wanted to do, what he hoped to achieve, his experience and unsentimental attitude towards the world of intelligence, the things that have to be done, someone has to do it, it’s hideous, but that’s what these people do. Frank knows that and he does that very well."

Slow Horses season 4 is available to stream now on Apple TV Plus. For more upcoming television that needs to be on your radar, here's our guide to the best new TV shows to watch out for.