A liquid filled bottle, comprising a cover member and a plastic bottle having a body, a rigid neck and a narrow opening sealed by the cover member, the narrow opening being defined in the upper face of the neck, the cover member comprising: - a one piece flexible closing element comprising: i) a central portion sealing the narrow opening of the bottle, and ii) optionally at least one margin portion extending around the central portion; and - a one piece flexible reinforcing element defined by at least one layer of film material; wherein the closing element has a top face delimited by a circumference and defining a substantially planar support surface; characterized in that the narrow opening is surrounded by a ring of the neck and the closing element is a peelable film and comprises a pull tab adapted for removing the cover member from the ring of the neck, so that the pull tab is included in the closing element and separate from the reinforcing element, the pull tab formed by the closing element protruding radially outwards beyond the ring, said central portion adhering with said ring, and in that said reinforcing element - comprises a reinforcing portion directly fastened to all or a part of said support surface and which entirely or partly covers said central portion, with the provision that at least an annular fixing portion of the central portion adhered to the ring is covered by the reinforcing element, the reinforcing portion defining a first surface, with the provision that if the reinforcing element comprises an extension portion defining a second surface that is entirely offset relative to the upper face of the neck, then the ratio between the second surface and the first surface is lower than 1:2. - a one piece flexible closing element comprising: i) a central portion sealing the narrow opening of the bottle, and ii) optionally at least one margin portion extending around the central portion; and i) a central portion sealing the narrow opening of the bottle, and ii) optionally at least one margin portion extending around the central portion; and - a one piece flexible reinforcing element defined by at least one layer of film material; wherein the closing element has a top face delimited by a circumference and defining a substantially planar support surface; characterized in that the narrow opening is surrounded by a ring of the neck and the closing element is a peelable film and comprises a pull tab adapted for removing the cover member from the ring of the neck, so that the pull tab is included in the closing element and separate from the reinforcing element, the pull tab formed by the closing element protruding radially outwards beyond the ring, said central portion adhering with said ring, and in that said reinforcing element - comprises a reinforcing portion directly fastened to all or a part of said support surface and which entirely or partly covers said central portion, with the provision that at least an annular fixing portion of the central portion adhered to the ring is covered by the reinforcing element, the reinforcing portion defining a first surface, with the provision that if the reinforcing element comprises an extension portion defining a second surface that is entirely offset relative to the upper face of the neck, then the ratio between the second surface and the first surface is lower than 1:2.