The legendary entertainer posted a video of her singing the song on Instagram along with the birthday wish.
Madonna also said it was her song for World AIDS Day.
“Silence =Death! 😷. Song For World AIDS Day! 🌎🌍🌏. #toxic #poisonparadise 🔥,” she wrote.
Madonna and Britney have famously performed together several times, including the time they shared a kiss seen around the world at the VMAs.