Whoever wins the mouth-watering showdown in London, whether it be Heineken Cup holders Leinster or 1999 champions Ulster, there could be another member of an elite "Brothers in Arms" club that already includes two Irishmen.
Ulster were captained by David Humphreys, now the club's director of rugby, when they beat Colomiers to the title at Lansdowne Road 13 years ago and now brother Ian could well feature at Twickenham.
Leinster full back Rob Kearney is already a Heineken Cup winner from their first success in 2009 (he missed the 2011 final through injury) and now he and younger brother Dave could both be involved at the home of English rugby.
Ulster duo Jan and Bryn Cunningham are the Irish pair already in the record books from 1999, while four-times winners Toulouse provide two sets of brothers from their first success in 1996 and the third in 2005.
The brothers already in the Heineken Cup record books are:
Philippe and Olivier Carbonneau (Toulouse, 1996)
Jan and Bryn Cunningham (Ulster Rugby, 1999)
Martin and Will Johnson (Leicester Tigers, 2001 and 2002)
Isitolo and Finau Maka (Toulouse, 2005)