We present the results of NTT/VLT UBV imaging of a 260 arcmin ^ { 2 } region containing the Galactic Luminous Blue Variable WRA 751 , in search for its birth-cluster , i.e .
a cluster of young and massive stars spatially and physically associated with it .
On the basis of the classical reddening-free parameter Q , we have identified a sample of 24 early-type stars with colours typical of spectral types earlier than B3 .
Interestingly , these stars are clustered within a radius of 1 ^ { \prime } from WRA 751 , corresponding to about 1 \% of the imaged field .
These stars tightly distribute around ( B - V ) \simeq 1.67 , which in turn defines a mean extinction A _ { V } \simeq 6.1 mag .
The 5 brighter ( V \leq 16.2 ) and bluer ( Q \leq -0.9 ) stars of the sample have been subsequently observed with FORS1 and classified as 3 late O- and 2 early B- stars .
The absence of stars earlier than O8 indicates an age of the cluster older than 4 Myr , although it could be due to an incomplete sampling of the upper end of the main sequence .
Nevertheless , the detection of OB stars of class I certainly indicates an age of a few million years .
At an assumed distance of 6 kpc , we estimate a cluster radius of 3.4 pc and a total mass of 2.2 \times 10 ^ { 3 } M _ { \odot } .
Our discovery is only the second known instance of a Galactic Luminous Blue Variable associated with its birth-cluster .