A self-winding mechanical horological movement including a pivotally oscillating weight, wherein the oscillating weight is provided with a decorative disc mounted on the oscillating weight and pivotally driven by the weight. The disc is fastened to a support that includes a stem inserted into a hole provided in the rotational shaft of the weight. The stem and the hole include non-circular section cylindrical portions corresponding with one another, so that the support and the disc are pivotally driven by the shaft. The disc forms a decoration that covers the entire surface of the movement, without requiring technical complexities. The disc can be free to undergo an axial movement in relation to the weight, so that the disc may be removed from the weight when the horological movement is dismantled from a watch case.