An assembly comprising: - a container with a neck and a mouth, said neck extending along a longitudinal axis (X-X) and terminating on top in an annular rim that delimits the mouth, - a tamper-evident closure coupled to said container for opening and closing said mouth, wherein said neck comprises: - a tubular wall extending along said longitudinal axis (X-X) between a lower portion and an upper portion, the annular rim being formed at the upper end of the upper portion, - threads formed outside the tubular wall, longitudinally beneath and adjacent to said annular rim, such threads having a minimum diameter D1 and a maximum diameter D2 and longitudinally extending between a lower end and an upper end, - a projection formed outside the tubular wall longitudinally beneath said lower end of the threads, said projection having a maximum diameter D3 that is greater than the minimum diameter D1 of the threads and smaller than or equal to the maximum diameter D2 of the threads, - a groove formed in the projection and extending in a circumferential or helical direction, with a minimum diameter D4 that is smaller than the maximum diameter D3 of the projection and smaller than the maximum diameter D2 of the threads, between a first end and a second end, wherein said tamper evident closure comprises: - a closure member configured to open and close said mouth, said closure member comprising a top wall and a sleeve, the sleeve being arranged coaxially outside the neck and longitudinally extending between said top wall and a bottom edge, said sleeve comprising threads removably engaged with the threads of the container, - a skirt arranged coaxially outside the neck and longitudinally beneath the sleeve, said skirt longitudinally extending with maximum diameter D5 between a top edge and a bottom edge, the top edge of the skirt being connected to the bottom edge of the sleeve by means of a frangible portion, which is configured to break upon first opening to allow removal of the closure member from the neck, said skirt having a first attachment portion, said first attachment portion being engaged in the groove to hold the skirt longitudinally attached to the neck upon first opening and extending with minimum diameter D6 between the first end and the second end of the groove, characterized in that said neck comprises a ramp extending in the circumferential or helical direction to join the second end of the groove with a portion of the projection, to thereby join the minimum diameter D4 of the groove to the maximum diameter D3 of the projection, and in that said skirt comprises a second attachment portion, said second attachment portion being engaged with the ramp to join the first attachment portion having the minimum diameter D6 with a skirt portion having the maximum diameter D5, so that, upon removal of the closure member from the neck, the skirt can be rotated relative to the neck to bring the first attachment portion to engage against the ramp and enlarge its diameter to the maximum diameter D5 to thereby disengage the first attachment portion from the groove and allow the skirt to be slid off the neck. - a container with a neck and a mouth, said neck extending along a longitudinal axis (X-X) and terminating on top in an annular rim that delimits the mouth, - a tamper-evident closure coupled to said container for opening and closing said mouth, - a tubular wall extending along said longitudinal axis (X-X) between a lower portion and an upper portion, the annular rim being formed at the upper end of the upper portion, - threads formed outside the tubular wall, longitudinally beneath and adjacent to said annular rim, such threads having a minimum diameter D1 and a maximum diameter D2 and longitudinally extending between a lower end and an upper end, - a projection formed outside the tubular wall longitudinally beneath said lower end of the threads, said projection having a maximum diameter D3 that is greater than the minimum diameter D1 of the threads and smaller than or equal to the maximum diameter D2 of the threads, - a groove formed in the projection and extending in a circumferential or helical direction, with a minimum diameter D4 that is smaller than the maximum diameter D3 of the projection and smaller than the maximum diameter D2 of the threads, between a first end and a second end, - a closure member configured to open and close said mouth, said closure member comprising a top wall and a sleeve, the sleeve being arranged coaxially outside the neck and longitudinally extending between said top wall and a bottom edge, said sleeve comprising threads removably engaged with the threads of the container, - a skirt arranged coaxially outside the neck and longitudinally beneath the sleeve, said skirt longitudinally extending with maximum diameter D5 between a top edge and a bottom edge, the top edge of the skirt being connected to the bottom edge of the sleeve by means of a frangible portion, which is configured to break upon first opening to allow removal of the closure member from the neck, said skirt having a first attachment portion,