Sheeran rescued the feline when it was just a kitten and he shared a photo of the pet delicately placing its paws on his guitar alongside a caption of a broken heart emoji.
Liberty wrote: “Our lovely little bud Baby Ba Boo aka Graham the Kitten passed away last night after being hit by a car. We are absolutely heartbroken.
“He was such a dude. Funny and clever and best mates with a massive German Shepherd. We are going miss you so much. Thanks for all the fun. #Babybaboo.”
Sheeran, known for his love of animals set up an Instagram account for two other cats Daorito and Calippo in 2018, allowing his fans to glimpse into the duo’s mischievous antics.
The candid snap shots showed the creatures climbing on furniture and making themselves at home as they settled in to Sheeran’s lavish residence.
Liberty is believed to have been looking after Graham while Ed performs on his world tour.
The death of the feline comes as Ed’s Divide Tour made history as the highest grossing of all time – surpassing U2’s 360 Tour.