'Kumar' Actor Kal Penn Robbed at Gunpoint in D.C.

TMZ has learned Kal Penn -- aka Kumar from that "White Castle" movie -- was robbed at gunpoint early this morning while walking in a neighborhood in Washington D.C.

Law enforcement sources tell TMZ Penn claims a man carrying a gun approached him around 1:20 AM and took his wallet and other personal property.

We're told Penn immediately reported the incident to authorities, who have launched an investigation into the matter.