SAN FRANCISCO (CBS SF) -- Burger fans are racing to grab 'proud' burgers from a chain in San Francisco whose ad campaign is going viral.

A Burger King in San Francisco began selling 'Proud Whoppers' over the weekend during the LGBT Pride celebration. The gay pride themed burger comes in a rainbow colored wrapper, and a matching crown.

"It's a smart thing to do. San Francisco is a very diverse community," 'Proud Burger' fan Youri Litvine said.

Others saw it as a public relations move.

"Personally, I find this to be corporate pandering to a group of people that they never cared about before," Tom Urani said. He bought a burger to get the crown.

The campaign is set to end Thursday.