TVLine Items: Lost Alum Gets Collar'd, The Voice Adds Michael Bublé, New Glee Mentors and More!

White Collar has a date with the Man in Black.

Titus Welliver has nabbed a guest-starring role on the new season of the USA Network drama (returning tonight at 9/8c), TVGuide.com reports. The Lost alum will play a United States senator with ties to Neal’s father.

Also appearing in Season 4 is Reed Diamond (Franklin & Bash), who will portray a ruthless construction bigwig with political ties.

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Ready for more of today’s TV dish? Well…

The Voice has unveiled the first new adviser for Season 3 (to bow Sept. 10). Standards crooner Michael Bublé will team with Blake Shelton when the singing competition returns. NBC has yet to reveal advisers for the series’ three remaining coaches: Adam Levine, Christina Aguilera and Cee-Lo Green.

• Dianna Agron and Grant Gustin are the latest Glee stars to drop by Oxygen’s Glee Project as guest mentors, per The Hollywood Reporter. The latter will appear in the July 17 episode, while Agron is set to make her debut on Aug. 7.

Shannyn Sossamon (How to Make It in America) has booked a multi-ep arc on ABC’s summer 2013 sudser Mistresses, per The Hollywood Reporter. Details surrounding her role are scarce, but she joins the previously cast Alyssa Milano, Yunjin Kim, Rochelle Aytes and Jes Macallan.

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• The Killing‘s Billy Campbell has been cast as Abraham Lincoln in National Geographic Channel’s Killing Lincoln, a two-hour drama (based on the book by the same name) that details the conspiracy behind the president’s assassination.

• This Thursday at 4 pm and midnight EST, VH1’s Unplugged will feature Gym Class Heroes performing fan favorites such as “Stereo Hearts,” “Billionaire,” “Ass Back Home” and their new single “The Fighter.”

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