Each year, more than 6 million dogs and cats wind up in animal shelters in the U.S. and approximately half of them must be euthanized because there aren’t enough good homes for them.

The single most important thing that we can do to save cats and dogs from the suffering and death caused by overpopulation is to get our animal companions spayed/ neutered.

Every February on the last Tuesday of the month, World Spay Day celebrates the importance of animal birth control and encourages all guardians of dogs and cats to have them spayed or neutered.

In honor of World Spay Day and throughout all of February, which is National Spay/Neuter Awareness Month‚ PETA have rounded up some of their favorite celebrity campaigns promoting animal birth control. Check out which stars have spoken up to spread this important message.