The abundance of lithium observed in very young stellar populations is few times larger than the primordial one estimated by recent Planck measurements. Since Lithium is easily destroyed in the stellar interiors, the search for astrophysical sources responsible for the observed lithium over-abundance was a challenge for decades. In this manuscript, we describe the results of an on-going survey dedicated to the study of nova outburst with high-resolution spectrographs at ESO/VLT, aimed at detecting beryllium-7. Our results represent a further confirmation of the occurrence of the thermonuclear runaway during nova explosions and imply that classical novae are one of the main factories of lithium in the Galaxy.