As I enter The Mayfair hotel suite where the sunshine is piercing through the windows, Andrew Scott is on his feet, dressed all in black, looking ready to dance the cha-cha-cha. It's a delightful welcome and his energy is infectious as he talks me through his recent role as the hot priest in Fleabag and his love of its genius creator, Phoebe Waller-Bridge.

But first, we chat about his role in Steel Country, a slice of Americana directed by Simon Fellows which leads a garbage-man to turn detective after a young child is found dead in a rust-belt town. It's a portrait of Donald Trump's America which leads us to chat about the current POTUS. 'I think the thing that's very dangerous about Donald Trump is that he presents no vulnerability whatsoever, he can never apologise for anything and he can't admit any degree of weakness. I think vulnerability is a great strength, it's how we connect with people.'

On the subject of vulnerable characters, I ask him if he knows what I'm going to ask next. He smiles knowingly and says, 'Go on!' With the numerous hot takes on his character in Fleabag as either an exploitative bastard or a depiction of flawed humanity, faith and love – I ask him whether The Priest is really a bit of both? 'The reason Fleabag is a success is two things can exist at exactly the same time. He can be vulnerable and powerful at the same time, he can be funny and sad at the same time, he can feel joy but he can feel terrible grief. For me, he's a character who's very flawed but he's deeply in love.'

The finale of Fleabag is perfection when it comes to love. It not only brings their flirtation to a poignant end and seals the sisterly bond with a dissection of the romantic notion of running to an airport to declare your love, it also delivers a heart-achingly insightful sermon on the crazy things we do when we're in love. Waller-Bridge's words in Scott's mouth draw out a desperate longing for connection in a way that is penetratingly honest and emotionally raw. 'That speech in some ways encapsulates the whole series. When we first spoke together, we spoke about our personal experiences and tried to encapsulate what love is.'

On how the second series has been received, Scott says, 'I was speaking to Phoebe yesterday on the phone and it's amazing that people have reacted to it in this way. I think it's because people see themselves in it. It's so truthful.' And on his working relationship with Waller-Bridge, Scott sums it up beautifully by saying, 'She's a very generous, fantastically fun person. On set she trusts you and its playful. It doesn't mean that it can't be sad and serious and all those worthy things. But actually on the day there's a great sense of being playful with each other and being alive. You can create stuff that isn't just about completing the call-sheet. That's what her great gift is. She's grateful to be alive and to experience the pain and the pleasure. I love her. I just love her.'

Steel Country is released in UK cinemas on Fri 19 Apr.