TV Guide reports that the actress will play a district attorney named Kathleen Roberts in a February instalment.
The "tough" Roberts will team up with Kono (Grace Park) when the two cross paths during a criminal investigation.
McManus currently plays the werewolf Jules on The CW's The Vampire Diaries and previously featured in a recurring role on Law & Order: Special Victims Unit. She also appeared in seventeen episodes of One Tree Hill as Lindsey Strauss and has made recent guest appearances on CSI: Miami and Castle.
Hawaii Five-0 returns to CBS on January 3.