Abstract. Component-based programming is about how to create application programs from prefabricated components with new software that provides both glue between the components, and new functionality. Models of components are required to support black-box compositionality and substitutability by a third party as well as interoperability. However, the glue codes and programs designed by users of the components for new applications in general do not require these features, and they can be even designed in programming paradigms different from those of the components. In this paper, we extend the rCOS calculus of components with a model for glue programs and application programs that is different from that of components. We study the composition of a glue program with components and prove that the components glued by the glue program yield a new component.