The freebie is being offered via the MatchPint app - but you'll have to be quick, as only 15,000 free pints are up for grabs.
The offer is available to all Guinness Pint Predictor players on the MatchPint app and can be claimed in more than 2,000 pubs across the UK and Ireland involved in the campaign over the weekend.
Niall McKee, head of Guinness Stout Europe, said, "We know lots of rugby fans are absolutely gutted not to be able to watch their team play this weekend, so we wanted to give them something to cheer about and continue to fuel their belief in their teams with a free pint of Guinness - bringing people together to chat rugby, even if they can't watch it.
How to get one
To claim your free pint of Guinness this weekend, MatchPint players need to select the 'prizes' tab in the Guinness Pint Predictor on the app.
Players can then search for their nearest pub and redeem their free pint by clicking the 'claim' button and following the instructions.
The offer will be available to redeem until midnight on Sunday (13 Oct).
For further information on the offer and where your nearest participating pub or bar is, visit the MatchPint website.