Rich Sommer Rich Sommer

Sherlock will soon get a little help from his friends!

Mad Men's Rich Sommer will reprise his role as Harlan Emple, one of Sherlock's "irregulars," on the upcoming third season of Elementary, has learned exclusively.

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Harlan, who assisted Sherlock in Season 2 after a mathematician was murdered, will come back into Sherlock's world when he finds a dead body during a math-based puzzle hunt.

Sommer, whose credits also include CSI and Law & Order: SVU, will appear in an episode slated for November.

Elementary returns Thursday, Oct. 30 at 10/9c on CBS.

(Full disclosure: is owned by CBS.)

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