this object and GQ Lup A (and also the separation between cc2 and the GQ Lup companion) in both right ascension and declination change as expected from the known proper motion of GQ Lup A. When assuming that cc2 does not move, then we obtain as proper motion for GQ Lup A $\mu _{\alpha} = -16.8 \pm 4.2$ mas/yr and $\mu _{\delta} = -24.3 \pm 2.2$ mas/yr, and for the known co-moving GQ Lup companion we get $\mu _{\alpha} = -15.2 \pm 4.6$ mas/yr and $\mu _{\delta} = -23.7 \pm 2.7$ mar/yr.[^3] Hence, the (proper and parallactic) motion of cc2 is negligible, therefore we can use it for measuring the parallax of GQ Lup A and its companion from the scatter in Figs. 3 and 4, namely deviations from a linear motion. This background object (GQ Lup/cc2) is listed in USNO-B1 as object 00543-0373323 with B$_{2}$ = 19.28 mag, R$_{2}$ = 17.77 mag, and I = 15.94 mag; it is also listed in NOMAD as object 0543-0380757 with B = 19.53 mag. We have determined K$_{\rm s}$ = $15.01 \pm 0.33$ mag (see Table 4). Hence, it is probably a mid- to late-K dwarf (or giant) star with weak extinction. 