A supportive undergarment configured to restrain movement of breast tissue in the superior direction is provided. The undergarment is configured to be used in conjunction with a conventional bra, especially an underwire-containing sports bra, without unnecessarily duplicating the support provided by the bra. The undergarment comprises a pair of supporting straps that are releasably anchored to the undergarment's lower circumscribing band via at least one anchor member. The supporting straps are configured to provide compression to the wearer's upper breast roots and arrest upward movement of the wearer's breasts.