New South Sydney co-owner James Packer says it is not just friendship and sentimentality behind his decision to buy into the NRL premiers; he believes he can make a dollar out of his latest investment as well.

Australia's third richest person, Packer on Thursday completed the purchase of a 37.5 per cent share in the Rabbitohs from Peter Holmes a Court, joining actor Russell Crowe as a joint majority owner of the famous inner-Sydney club by outlaying more than $7.5 million.

Getting down to business: James Packer and Russell Crowe. Credit:Getty Images

Already a major sponsor of the club, through his company Crown Resorts, Packer's entry into NRL ownership gives him and close friend Crowe a cherished plaything and places Packer at the helm of a team his late father Kerry famously supported.

The billionaire, however, was on Thursday night eager to point out the potential of Souths as a brand, with the grand final winners now estimated to be worth in excess of $20 million.