  We present the first optical validation of an X-ray Line-Emitting Object
(XLEO) discovered in the XMM-Newton observation of the Chandra Deep Field
South. The object is an AGN at z_x ~ 0.66. An optical spectrum of the source
indeed confirms and refines (z_o = 0.665) the redshift obtained from the X-ray
line. The X-ray and optical properties of the source are presented and
discussed.
