Former New York City Mayor Michael Bloomberg is backing a campaign to pass a sugary-drinks tax in Philadelphia.

Bloomberg, who tried to ban over-sized sodas in New York as mayor, and provided millions of dollars to support successful soda-tax initiatives in Mexico and Berkeley, Calif., has contributed to the pro-tax nonprofit Philadelphians for a Fair Future, said the group's spokesman, Kevin Feeley.

The nonprofit is launching a $825,000 ad campaign starting Thursday on behalf of Mayor Kenney's plan to enact a three-cents-per-ounce tax on sugary drinks.

Feeley declined to say how much money Bloomberg has contributed.

The ad campaign was also being supported with funds donated by the Action Now Initiative, a nonprofit focused on antiobesity and education issues funded by Houston billionaire couple John and Laura Arnold.

"It's wonderful to have the support of a nationally respected business leader," Kenney said in a statement, referring to Bloomberg. "I'm hopeful these ads will correct the misinformation that the soda industry is spending millions to spread."

Feeley said the money from Bloomberg and the Arnolds' nonprofit offers a chance to "balance the scales."

"What it provides us is the ability to compete," he said. "We understand the reality of what's happening on the other side. The other side has almost unlimited financial resources."

The American Beverage Association has already spent more than $2.5 million on an anti-soda tax advertising campaign, dubbing the levy on sugary drinks a "grocery tax."

Feeley said the pro-tax ads to start this week are only a first step.

"We're prepared to do more as we need to do more," Feeley said.

The thirty-second spot features images of young children smiling in classrooms as a woman's voice says, "Philadelphia's chance to help lift our children with city-wide Pre-K is now."

Bloomberg has been a leader in the anti-sugar crusade. His charitable foundation, Bloomberg Philanthropies, funded commercials in Berkeley that ran during the World Series. This time, Bloomberg himself - not his foundation - is putting up the money.

Philadelphia's health commissioner, Thomas Farley, headed New York's health department under Bloomberg.

The Arnolds, who made billions in energy trading, invested in the Berkeley pro-soda tax movement and poured millions into research supporting dietary recommendations on cutting sugar.

While both the Arnolds and Bloomberg favor the health benefits of a soda tax, Kenney has largely pushed his proposal on the merits of what it would fund: pre-K for the city's 3- and 4-year-olds, community schools, and a bond to pay for park and recreation center upgrades.