  Classical novae are phenomena caused by explosive hydrogen burning on an
accreting white dwarf. So far, only one classical nova has been identified in
X-rays before the actual optical outburst occurred (V2487 Oph). The recently
discovered nova, V2491 Cyg, is one of the fastest (He/N) novae observed so far.
Using archival ROSAT, XMM-Newton and Swift data, we show that V2491 Cyg was a
persistent X-ray source during its quiescent time before the optical outburst.
We present the X-ray spectral characteristics and derive X-ray fluxes. The
pre-outburst X-ray emission is variable, and at least in one observation it
shows a very soft X-ray source.
