Aims: The appearance of two recent supernovae, SN 2011dh and 2005cs, both in M 51, provides an opportunity to derive an improved distance to their host galaxy by combining the observations of both SNe. Methods: We apply the Expanding Photosphere Method to get the distance to M 51 by fitting the data of these two SNe simultaneously. In order to correct for the effect of flux dilution, we use correction factors (ζ) appropriate for standard type II-P SNe atmospheres for 2005cs, but find ζ ~ 1 for the type IIb SN 2011dh, which may be due to the reduced H-content of its ejecta. Results: The EPM analysis resulted in DM 51 = 8.4 ± 0.7 Mpc. Based on this improved distance, we also re-analyze the HST observations of the proposed progenitor of SN 2011dh. We confirm that the object detected on the pre-explosion HST-images is unlikely to be a compact stellar cluster. In addition, its derived radius (~277 R⊙) is too large for being the real (exploded) progenitor of SN 2011dh. Conclusions: The supernova-based distance, D = 8.4 Mpc, is in good agreement with other recent distance estimates to M 51.