One of the most interesting things about Sherlock has been watching Sherlock grow from being a lonely sociopath into someone with a big group of friends around him. The character has had a very clear growth over the past three seasons – and Benedict Cumberbatch has now promised that this will only continue in Series Four.

In an interview with Variety (via WeGotThisCovered), Cumberbatch spoke about the lasting effect Sherlock’s friendship with John has had on him. Here’s what he had to say:

“He is becoming slightly more… well, in a very clear way… responsible for his actions… But I think he understands that it’s a slow, slow process that began in the very first instance when he met John (Watson), who supplies the missing piece of that jigsaw that is him. That friendship, that partnership in crime, has been the humanizing element all the way through, and I think he is now becoming more of a human-being… As he’s evolving he loses sight of what he is letting go of, which is this very cold, results at all cost, all about the end-game, rather than how he gets there, and who he tramples over. And because he is so loyal to somebody he cares about, he’s blind-sided himself with his own humanity.”

So just how much will Series Four explore Sherlock’s newfound humanity? We don’t have long to wait until we find out.

Sherlock returns this January 1st. It airs at circa 9PM on BBC One in the UK and PBS Masterpiece in the US.