Sean "P. Diddy" Combs' birthday at Mansion was a nightmare for a young designer who decorated the Chelsea hot spot.

"He was given a budget of $7,000 and 12 hours to create an all-white décor, including 1,000 white roses, blow-ups of Diddy and Barack Obama, and $2,000 of white fabric," our spy said.

"Diddy declared it dreadful and went into a major hissy fit, screaming, 'Show me the receipts!' and 'Get the money back!' to his assistant.

Then he began ripping the fabric off the walls saying he hated it.

He berated the poor young decorator to the point that the guy gave back $2,000 of the money he had spent." Diddy's rep did not respond to requests for comment.

Click here to read the full report from the New York Post.