The Scottish actor will play a bookie in forthcoming episode 'Home Invasion', according to TVDoneWright.
Flanagan plays biker Chibs on FX drama Sons of Anarchy and has also appeared on 24 and Lie to Me.
His SVU episode will additionally feature a guest stint from Isiah Whitlock, best known for playing Senator Clay Davis on HBO's The Wire.
Jake T Austin, who appeared in the Disney Channel's Wizards of Waverly Place, will also appear in a supporting role.
Harry Connick Jr recently began a multi-episode story arc on Law & Order: SVU, while country singer Miranda Lambert will also make her acting debut in a forthcoming instalment.
Law & Order: SVU will return to NBC on February 8 at 10/9c.
> Sons of Anarchy star Theo Rossi lands Alcatraz role
Watch a promo for the next episode of Law & Order: SVU below: