The campaign of Republican presidential contender John McCain has released a new ad featuring Paris Hilton and Britney Spears that refers to Democratic candidate Barack Obama as "the biggest celebrity in the world."

The ad, entitled "Celeb," opens with brief flashes of Paris and Britney photos before cutting to a montage of large crowds and Obama appearances, with a narrator asking "but is he ready to lead?" 

The political ad goes on to criticize Obama for opposing offshore drilling and proposing a tax on electricity.

In response, the Obama campaign criticized McCain for resorting to negative campaign tactics. "On a day when major news organizations across the country are taking Senator McCain to task for a steady stream of false, negative attacks, his campaign has launched yet another. Or, as some might say, 'Oops! He did it again,'" said a statement from the Obama campaign.