Are Bill and Ben the oldest twin horses in the world? The 24-year-old brothers are hoping to trot into the record books with their claim to the title.
Although twins aren't uncommon in the human world, experts say it is really unusual for twin foals to be born.
The Veteran Horse Society, which looks after Bill and Ben, is asking Guinness Records to check out their claim.
The twins used to give rides to kids at London Zoo but are now retired and living near Cardigan in Wales.
Twins Bill and Ben
Veteran Horse Society spokesperson Julianne Aston, said the boys are so similar it can be hard to tell them apart.
She said: "They are so alike that we have tie a blue ribbon in one of their manes so we can distinguish between them."
The horses, which have white hair and blue eyes, enjoy snacking on carrots, apples and are given sugar-free mints as a treat!
Julianne added: "They are great with us, but they seem to argue and bicker between themselves and often have temper tantrums. I suppose they're similar to human brothers."
Guinness is investigating their claim and the brothers will soon find out if they've set a new record.