It was reported earlier today that the pair are getting "very serious" about one another.
Ladbrokes has now put together a number of odds for the couple.
The shortest odds are for the pair to split before the end of 2012 at just 3/1, whilst the chance of an engagement before the end of 2013 has been offered at 10/1.
Other odds include 100/1 for all four Spice Girls to be Halliwell's bridesmaids and 25/1 for a 2013 pregnancy announcement.
The release of these odds comes before an official announcement from either Halliwell or Brand about their rumoured relationship.
The pair were photographed together with Halliwell's bandmates backstage at the Olympics Closing Ceremony.