A Network Node (NN) 208 and a method therein for beam selection. When an upcoming ability to serve a Wireless Device (WD) 210 using a current NN beam is predicted to be lost based on historic data, the NN selects an upcoming NN beam out of one or more candidate NN beams that are able to serve the WD when the NN has lost ability to serve the WD using the current NN beam. The NN configures a dedicated Beam Reference Signal (BRS) for the upcoming NN beam, which is to be detected in beam selection by the WD when the NN loses ability to serve the wireless device using the current NN beam. By means of the current NN beam, the NN transmits, to the WD, a configuration of the dedicated BRS. Further, by means of the upcoming NN beam, the NN transmits, to the WD, the dedicated BRS.