And with 24 percent of those signing the giant shirt being Ireland supporters, we have some catching up to do!
There are 12 Ireland players out in South Africa including Brian O'Driscoll, Donncha O'Callaghan, Stephen Ferris, David Wallace, Jamie Heaslip, Luke Fitzgerald, Ronan O'Gara, Keith Earls, Rob Kearney, Tommy Bowe, Gordon D'Arcy and tour captain Paul O'Connell.
You can back all the Lions players by logging on to www.lionsrugby.com/hsbc and signing the giant shirt.
One lucky person from each of the home nations who signs the shirt online will also win a VIP trip for two to the third and final Test. So get signing and ensure your nation roars loudest for the Lions!
The 18mx15m shirt was launched in London last month by Brian O'Driscoll who said: "The Lions tour to South Africa this summer is sure to be another titanic battle, and nothing can beat the feeling of touring with the Lions, not least to the backyard of the Rugby World Cup holders.
"I can vividly remember the drama and excitement of the last Lions tour to South Africa 12 years ago, as well as captaining the Lions on the last tour to New Zealand four years ago.
"And with the launch of this initiative to get behind the shirt, HSBC has provided a perfect opportunity for fans to get involved this summer.
"That's why I am calling on all fans, whether supporters of Ireland, England, Scotland or Wales, to show their support for the squad and sign the shirt."
The shirt has been touring Ireland and the UK since its launch, with visits to Edinburgh, Swansea, Llanelli, Cardiff, Manchester, Dublin, Belfast, Glasgow, Bath, Bristol and Leicester collecting support as it goes.
It made a special appearance earlier this week in Belfast where it got to parade through the centre of the city, ending up at Donegal Square.
The Lions management team and playing squad have already signed the shirt, so now is a great time for fans to have their name up alongside the greatest rugby players and to truly follow this summer's Lions tour.
Current signees include past Lions Martin Johnson, Will Greenwood, Jeremy Guscott, Willie John McBride and HSBC ambassadors Jason Robinson, Gavin Hastings and Gareth Edwards.