The singer and celebrity chef are featured sporting the familiar white milk moustache with the strapline “make mine milk”.
The campaign aims to promote the health benefits of drinking low-fat milk and will include outdoor, and digital elements.
Other celebrities are set to be revealed as part of the £7.5m Milk Marketing Forum campaign.
Ramsay says: “There is a lot of love for milk in this country, but people often assume that it’s only good for kids who need a bit of calcium. The truth is that milk, especially low-fat milk, is fantastically good for you.”
Between 2001 and 2008, there has been a 1% decline in milk consumption each year.
The Scottish milk campaign starring British number one tennis player Andy Murray and model Nell McAndrew led to a 3.4% increase in milk sales.
Celebrities including singer Beyonce Knowles and actor Hugh Jackman have previously starred in the US “Got milk” campaign.