After three long, long years, the BBC's hit series "Sherlock" is finally returning for its full fourth season on January 1. We've seen glimpses of what's to come so far thanks to new official photos. There's now a baby in the cast -- and Sherlock isn't too thrilled about that, judging by his reaction in those pics.RELATED: Sherlock Gives Baby Watson the Side-Eye in Season 4 PhotosNow the official "Sherlock" Twitter account has posted an ominous teaser for the next batch of episodes. It features John Watson (Martin Freeman) and Sherlock Holmes (Benedict Cumberbatch) sitting in the living quarters of 221B Baker Street as it floods with water.

The season four trailers indicate the series will pick up right after the death of season three villain Magnussen, and could possibly deal with the return of Moriarty, despite his apparent death.

The season four premiere will mark the first new "Sherlock" episode since the special that aired in January 2016 -- and it will also be the first episode since both Martin Freeman and Benedict Cumberbatch joined the Marvel Cinematic Universe as Everett Ross and Doctor Strange.

Created by Mark Gatiss and Steven Moffat and starring Benedict Cumberbatch and Martin Freeman as Sherlock Holmes and Watson, "Sherlock" returns for it's fourth season on January 1, 2017.