The forward will officially become a Red at the start of the January transfer window from PSV Eindhoven, subject to a work permit.
And the Netherlands international has selected No.18 as his squad number, which was most recently occupied by Takumi Minamino.
Dirk Kuyt, Alberto Moreno, John Arne Riise and Antonio Nunez are also among those to have worn the shirt for Liverpool in the Premier League era.