Fast food workers worldwide demanding more pay are ready to strike on May 15.

Fast Food Forward, a group that represents U.S. fast-food workers, announced Wednesday that workers from all over the world are joining its efforts to push for higher pay and worker rights.

The group said it plans to hold nationwide strikes in at least 150 cities May 15 -- the date signifies the $15 per hour pay they are demanding. Outside the U.S. protests are planned at McDonald's, Burger King and KFC locations. 

There's 4 million fast food workers in the U.S. and thousands of them are expected to take part in the nation's one-day strike.

"We've gone global," said Ashley Cathey, a McDonald's worker from Memphis, Tennessee, who makes $7.75 an hour after six years on the job. "Our fight has inspired workers around the world to come together." 

This issue isn't expected to go away anytime soon. Later this month, McDonald's will host its annual shareholders meeting in Oak Brook, Illinois and the pay issue could be a talking point.

McDonald's spokeswoman Heidi Barker Ba Shekhem says nearly 80 percent of McDonald's locations are owned and operated by small business owners.

"This is an important discussion that needs to take into account the highly competitive nature of the industries that employ minimum wage workers, as well as consumers and the thousands of small businesses which own and operate the vast majority of McDonald's restaurants," she said.

The median pay for a fast food worker is about $9 per hour or about $18,500 per year. That's about $4,500 less than the Census Bureau's poverty income threshold level of $23,500 for a family of four.

Some experts believe that if the minimum wage is raised, franchisees that operate and own the restaurants would suffer.

President Obama indirectly addressed the fast food workers concerns by proposing to Congress to raise the minimum wage in the U.S. from $7.25 to $10.10 per hour. So far this year, Connecticut, Maryland, Hawaii and New Jersey have raised their state minimum wage rates.

The planned protests on May 15 are expected to be the largest fast food strikes ever.