John Noble John Noble

The mystery of who Sherlock's father is has been solved! John Noble has joined Elementary as a series regular for Season 4, where he will play the famed detective's wealthy, estranged dad. This is perfect casting, and makes us feel a little better about why Sherlock's dad needs to appear and how his presence will upset his son.

Though never seen, the character has been referenced in the first three seasons of CBS' crime drama as being instrumental in Sherlock's first stint in rehab and in pairing his son with Joan Watson, his former sober companion and now investigative partner.

The Fringe and Sleepy Hollow star will make his first appearance in the show's Season 4 premiere, when Mr. Holmes arrives in New York City to deal with the aftermath of Sherlock's recent relapse after dealing with one of his former drug associates on a case.

Who else is dropping in on Sherlock next season?

"We could not be more delighted to have John Noble taking on such an important role," said Robert Doherty, Elementary creator in a statement. "It's going to be an exciting season."

What do you think Elementary fans? Are you excited about Noble's casting?

(Full disclosure: TVGuide.com is owned by CBS)

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