The resonator (1) for a timepiece results from coupling a first, low frequency resonator (2) with a second, higher frequency resonator (3). The first resonator (2) has a first balance (4) associated with a first balance spring (5). The second resonator (3) has a second balance (6) associated with a second balance spring (7). A third balance spring is arranged between the first (4) and second (6) balances to couple said first (2) and second (3) resonators.