A combine harvester comprising: - a feeder at the front of the harvester, the feeder comprising a housing and a cradle frame mounted at the front of the feeder, wherein the cradle frame is configured to receive a header comprising a header drive axle oriented transversely to the forward direction of travel of the harvester when the header is coupled to the cradle frame, and wherein the cradle frame is movable relative to the feeder housing, - a driveline configured to drive the rotation of the header drive axle when the header is coupled to the feeder, wherein the driveline comprises a belt drive arranged laterally with respect to the feeder housing, and configured to transmit the rotation of a first axle of the driveline that is rotatable about a rotation axis which is fixed relative to the feeder housing, to the rotation of a second axle of the driveline, configured to be coupled to the header drive axle, the second axle being rotatable about a rotation axis that is fixed relative to the cradle frame, wherein the belt drive comprises a first pulley coupled to the first axle, a second pulley coupled to the second axle, a belt mounted on the first and second pulley and a tensioning system for the belt, characterized in that: - the first pulley is coupled to the first axle through a first coupling (35,75) that allows a misalignment between the rotation axis of the first axle and the rotation axis of the first pulley, - the second pulley is coupled to the second axle through a second coupling (36,75) that allows a misalignment between the rotation axis of the second axle and the rotation axis of the second pulley, and - said belt drive further comprises an extendable bridge structure mounted between the first and second pulley (25,27), wherein the pulleys (25,27) are configured to rotate relative to the bridge structure and wherein the bridge structure is extendable and retractable in the longitudinal direction of the belt drive, so that the pulleys (25,27) remain essentially aligned in the same plane, regardless of the position of the cradle frame. - a feeder at the front of the harvester, the feeder comprising a housing and a cradle frame mounted at the front of the feeder, wherein the cradle frame is configured to receive a header comprising a header drive axle oriented transversely to the forward direction of travel of the harvester when the header is coupled to the cradle frame, and wherein the cradle frame is movable relative to the feeder housing, - a driveline configured to drive the rotation of the header drive axle when the header is coupled to the feeder, wherein the driveline comprises a belt drive arranged laterally with respect to the feeder housing, and configured to transmit the rotation of a first axle of the driveline that is rotatable about a rotation axis which is fixed relative to the feeder housing, to the rotation of a second axle of the driveline, configured to be coupled to the header drive axle, the second axle being rotatable about a rotation axis that is fixed relative to the cradle frame, wherein the belt drive comprises a first pulley coupled to the first axle, a second pulley coupled to the second axle, a belt mounted on the first and second pulley and a tensioning system for the belt, characterized in that: - the first pulley is coupled to the first axle through a first coupling (35,75) that allows a misalignment between the rotation axis of the first axle and the rotation axis of the first pulley, - the second pulley is coupled to the second axle through a second coupling (36,75) that allows a misalignment between the rotation axis of the second axle and the rotation axis of the second pulley, and - said belt drive further comprises an extendable bridge structure mounted between the first and second pulley (25,27), wherein the pulleys (25,27) are configured to rotate relative to the bridge structure and wherein the bridge structure is extendable and retractable in the longitudinal direction of the belt drive, so that the pulleys (25,27) remain essentially aligned in the same plane, regardless of the position of the cradle frame. - the first pulley is coupled to the first axle through a first coupling (35,75) that allows a misalignment between the rotation axis of the first axle and the rotation axis of the first pulley, - the second pulley is coupled to the second axle through a second coupling (36,75) that allows a misalignment between the rotation axis of the second axle and the rotation axis of the second pulley, and - said belt drive further comprises an extendable bridge structure mounted between the first and second pulley (25,27), wherein the pulleys (25,27) are configured to rotate relative to the bridge structure and wherein the bridge structure is extendable and retractable in the longitudinal direction of the belt drive, so that the pulleys (25,27) remain essentially aligned in the same plane, regardless of the position of the cradle frame.