In an episode slated to air early in the new year -- before Lie To Me presents its season finale on January 31 -- Holmes will play Zach Morstein, a hoodie-wearing genius who lands in Cal's crosshairs when one of the website's cofounders is the victim of foul play.
As Lightman labors to rattle the online entrepreneur, his every bit of micro-expression detection is detected and ably deflected by his brilliant prey.
Any resemblance to Mark Zuckerberg, the founder of Facebook and subject of the hit film The Social Network, is purely intentional -- save for, well, the nasty bit of murder.
Holmes recurs on The CW's Nikita as Thom, a recently promoted Division field agent who has a bit of a soft spot for Lyndsy Fonseca's Alex.
In other casting news: 24 alumna Leslie Hope (RIP Teri Bauer, tear) will guest-star on ABC's Off The Map, the new Shonda Rhimes-produced medical drama premiering January 12. Hope will play a career-oriented, Type A personality who has traveled to South America to adopt a child.