The timepiece includes a tourbillon including a carriage that bears a sprung balance and a magnetic escapement device, the latter including an escape wheel set, formed of an annular magnetic structure, and a magnetic element coupled with the magnetic structure and having an oscillating movement that is synchronous with the oscillation of the mechanical resonator. The mechanical escapement is arranged so as to have alternately energy accumulation phases, from a conversion of mechanical energy supplied by the barrel into magnetic potential energy in the magnetic escapement, and transfer phases of energy accumulated in the magnetic escapement to the magnetic resonator. During the energy transfer phases, the magnetic element is subjected to a magnetic force such that the magnetic escapement then converts into mechanical energy magnetic potential energy accumulated in the preceding energy accumulation phase to be able to maintain the oscillation of the mechanical resonator.