An active bolster for an interior trim surface of an automotive vehicle has a plastic-molded outer trim panel with a closed-loop bonding section on an inside surface. A plastic-molded expandable bladder member has a central attachment section configured to attach to a support structure of the vehicle, a bonding flange along an peripheral edge, and a baffle section between the central attachment section and the bonding flange. The closed-loop bonding section and the bonding flange are configured to define a substantially closed toroidal region therebetween. An attachment body is molded in-situ to substantially fill the toroidal region. As a result of the in-situ molding of the attachment body in the toroidal region, the trim panel and bladder member become bonded via the attachment body resulting in a high bonding strength.