BACKGROUND : Domestic pets can contract severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection; however, it is unknown whether the UK B.1.1.7 variant can more easily infect certain animal species or increase the possibility of human‐to‐animal transmission. METHODS : This is a descriptive case series reporting SARS‐CoV‐2 B.1.1.7 variant infections in a group of dogs and cats with suspected myocarditis. RESULTS : The study describes the infection of domestic cats and dogs by the B.1.1.7 variant. Two cats and one dog were positive to SARS‐CoV‐2 PCR on rectal swab, and two cats and one dog were found to have SARS‐CoV‐2 antibodies 2–6 weeks after they developed signs of cardiac disease. Many owners of these pets had developed respiratory symptoms 3–6 weeks before their pets became ill and had also tested positive for COVID‐19. Interestingly, all these pets were referred for acute onset of cardiac disease, including severe myocardial disorders of suspected inflammatory origin but without primary respiratory signs. CONCLUSIONS : These findings demonstrate, for the first time, the ability for pets to be infected by the B.1.1.7 variant and question its possible pathogenicity in these animals.