June 10 [12:00 EDT] -- British R&B singer Mark Morrison has been sentenced to another three weeks in London's Wormwood Scrubs Prison.

Morrison, who is currently sitting at number four on the U.S. singles chart with "Return of the Mack," is already serving three months behind bars for threatening a policeman with a stun gun last fall.

The extra time, to be served concurrently, was handed out for a more recent incident in London in which the singer punched out and head-butted another man.

Morrison apparently invited two women to a party, and the man who was escorting them took umbrage. The jilted escort then went on to make unkind remarks about Morrison¹s music, and an altercation followed.

Morrison is still scheduled to release a new mini-album next month, but his convictions could prevent him from being issued a visa to perform in this country in the future.