Andrew Harris, from the Welsh Blood Service, told BBC Radio Wales how the collaboration came about.
“There’s a lot of fans in the Welsh Blood Service of Metallica, it turns out,” he explained, describing how a colleague, James, came into the office and said “‘wouldn’t it be great if we worked with Metallica?'”
“I told him, ‘that’s a brilliant idea… let me know how it gets on’.
“He found the charity and here we are – it’s happening!
“We actually found out about this because of the success of a similar promotion in the United States and Australia”
“It’s lead to thousands of people donating blood, that may or may not think about donating, which is what’s really important about this partnership.”
“It’s really important we keep a steady supply.”