John and Mary Watson are proud new parents in these Sherlock series 4 photos

Judging from some of the latest pictures, the next adventures of everyone’s favourite (and only known) Baker Street detective won’t all be doom and gloom. Especially for new parents John (Martin Freeman) and Mary Watson (Amanda Abbington).

In fact, the couple are looking downright happy at the christening for their newborn daughter, Rosamund Mary Watson.

And that’s all the happy photos released before we reach a section called 'Benedict Cumberbatch's Sherlock Slightly Frowning at Things'. First there's him slightly frowning while he's sitting by Mycroft.

Then there's Sherlock offering you a brooding frown outside the MI6 building...

Then he's frowning at someone we can't see (judging by that 'Top Secret' sign, somebody inside MI6)...

And – a bold choice this – Sherlock adopts the same pose inside 221B Baker Street, but swaps the frown for a death stare...

Before quickly being back again with the frown, this time with the Watsons' dog (where are John and Mary?)...

And finally he goes for minimal frown while doing some science.

Also, we’ve got a glimpse at a new character: DI Hopkins, played by Eleanor Matsuura (Alan Partridge: Alpha Papa).

Well spotted, Sherlock fans: DI Hopkins is indeed a character from the books. In the original Arthur Conan Doyle stories, Inspector Hopkins is a Scotland Yard detective and wanna-be student of Sherlock. Although Sherlock doesn’t find her methods of deduction up to par, she does refer several cases to him. Will she do the same in the TV series? We’ve not got long to find out…

Sherlock series four starts 8.30pm New Year's Day 2017, BBC1