The 28-year-old 'Girls' creator and star will appear in an upcoming episode set to air in March on ABC, Entertainment Weekly reported.
Details of her role are being kept under wraps, but it's thought she could be linked to Olivia Pope & Associates.
Dunham has previously expressed her desire to join the cast of 'Scandal', admitting that it was her "life's great passion" to feature on the political thriller series.
The Emmy-winning series - created by Shonda Rhimes - follows crisis manager Olivia Pope (Kerry Washington) and her team of lawyers, hackers and political insiders.
Meanwhile, Dunham will also appear in an upcoming episode of 'The Simpsons'. She will play Candace, a pharmacist and a love interest for Homer, whose marriage with Marge is once again on the rocks.