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The thermal fluctuations effects on the instability of the free surface of a flat liquid metallic film upona solid substrate are considered within the long wave approximation. Unlike the case of polymeric films,we find that this stochastic noise, while remaining white in time, must be colored in space at least in someregimes. The noise term has a nonzero correlation length, c , which combined with the size of the system,leads to a dimensionless parameter β that accounts for the relative importance of the spatial correlation(β ∼ −2c ). The linear stability analysis (LSA) of the film shows that the wavelength of the peak of thespectrum is larger than that corresponding to the deterministic case when c is larger than a critical valuethat depends on the system size while, for all c ?s, the peak approaches the deterministic one for largertimes (Fig. 1). The numerical simulations of the complete non-linear problem are in good agreementwith the LSA power spectra for early times at different values of β. For late times, the stochastic LSApredicts well the position of the dominant wavelength, showing that nonlinear interactions do not modifysubstantially the trends of the early linear stages. We compared LSA predictions with the experimental data from the instability of laser-melted coppernanometric films on a silicon oxide substrate. As a result, we found that the early stages of the experimentevolved with an almost white noise in space, while a strong spatial correlation appeared in the spectrafor later times. Thus, correlated noise seems to be an important factor in the central regions of the laserspot, i.e. those with larger liquid lifetimes. Taken together, our results provide a clear indication that thestochastic differentialframework for metallic thin-film phenomena at the nanometric scale requires theinclusion of thermal noise with extended spatial correlations.