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Classical Cepheids are well known cosmological yardsticks. The most accurate calibration of the Cepheid period-luminosity relation is obtained for the Cepheids which are located inside star clusters. The progenitors of Cepheids are thought to form in binaries, indicating that interactions between binary stars in clusters likely play an important role in the ability of mid-B stars to evolve to Cepheids. Using numerical modelling by the code NBODY6, we investigate the evolution of mid-B stars under the influence of star cluster dynamics for clusters of various initial masses. We find that the fraction of Cepheids located in clusters in our models (30 %) is noticeably larger than what is observed in the Local Group (around 9 %). Most clusters host at a given time at most one Cepheid and clusters with more Cepheids are rare. Cluster environment significantly increases the eccentricity of the binaries while other binaries are disrupted; in total approx. 42% of Cepheids is located in binaries, which is much less than the observed value (approx. 80%). We will discuss the nature of companions to Cepheids and also the implications for birth multiplicity of B type stars.