Long-baseline interferometry with facilities such as the ESO VLTI is beginning to have the capability to measure directly in the range of milliarcsecond and less the angular separation and the angular diameter of some selected eclipsing binary systems. We have begun to carry out such observations with the AMBER instrument. In the special case of double-lined eclipsing binaries with well-detached components, from radial velocity and light curves it is possible to obtain a full solution of all orbital and stellar parameters, with the exception of the effective temperature of one star, which is normally estimated from spectral type or derived from atmospheric analysis of the spectrum or reddening-corrected photometric colors. In particular, we aim at deriving directly the effective temperature at least of one component in the proposed system, thereby avoiding any assumptions in the global solution through the Wilson-Devinney method. We have obtained an independent check of the results of this method concerning the distance to the system. This represents the first step toward a global calibration of eclipsing binaries as distance indicators. Our results will also contribute to the effective temperature scale for hot stars. The extension of this approach to a wider sample of eclipsing binaries could provide an independent method to assess the distance to the LMC.