Sherlockfinally returns on Jan. 1, and there are some big changes afoot for season 4.
Here are some highlights from our chat.
EW RADIO: So, we have a Baby Watson on the way, dont we?

Credit: Robert Viglasky
MARTIN FREEMAN:Wearegoing to have a Baby Watson.
John and Marys relationship has moved on.
How will be being a father change John?
Thats just a big responsibility.
Its not just a proceduralCSItype crime of the week thing.
Its also always been about that friendship between those two and the other people in it.
John is a little bit changed, but you cant change the shape of the show too much.
Weve heard that season 4 is going to be very dark.
What does that mean exactly?
Also, the external stuff that is happening in the show.
The cases in the show have always been fairly dark.
Some of them are scary and youre seeing some of the worst aspects of human nature.
And theres just more of that, really, but even more so.
I dont want to give anything away, but there are some changes afoot.
How is Toby Jones villain Culverton Smith different from the baddies weve seen before like Moriarty and Magnussen?
Toby is a really good actor and a very lovely man.
Its nice to have him around on set.
For someone who essentially is such a sweet person, he does creepy very well.
Hes someone who truly turns Sherlock and Johns stomachs and who they really do want to bring down.
They want to take him down.
What do you make of that?
I really liked that as well, the ending of that episode.
But I dont think it is that.
But I dont know.
How do you balance possibly doing a season 5 of this versus wanting to do other things?
Everyone involved in the show is acutely aware of how well-written it is and how well-produced it is.
And that doesnt come along every day.
But at the same time, we do want to do other stuff.
And thank God were all busy.
[Co-creators] Steven Moffat and Mark Gatiss are busy.
I wouldnt want to make any promises either way on that.
I think things ending is not a thing to be afraid of.
Can you imagine the Beatles now?
Certain things should end.
I think everything is supposed to be finite.
To hear the entire interview with Freeman, listen toEW Morning LiveOn Demand on the SiriusXM app.