The country singer is to make her acting debut as a star who is sexually assaulted by a reality television producer (Michael McKean), reports TV Guide.
Lambert took to Twitter to confirm her casting, writing: "Y'all I'm so freaking excited to be on my favourite show ever!!!"
Harry Connick Jr will also appear in Law & Order: SVU for a four-episode arc as a love interest for Mariska Hargitay's character Olivia Benson.
Law & Order: Special Victims Unit airs Wednesdays at 10/9c on NBC. An airdate for Lambert's episode has not yet been announced.
Lambert is currently recovering from a bout of food poisoning that she has compared to a "near death experience".
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Watch Miranda Lambert's 'Baggage Claim' music video below: