Millennium Stadium Chief Executive Paul Sergeant said: "The date of Saturday 13 May 2006 is now firmly secured in our diary and we have signed an agreement to that effect.
"The FA have every intention of staging the showcase event at Wembley and we wish all those involved in the construction of Wembley every success. These projects can be very complicated, but it is in everyone's interests that the new Stadium goes to plan.
"However, it makes perfect business sense for the FA to have a firm back-up venue for the FA Cup Final and this agreement alleviates any pressure on the governing body should Wembley not be ready. This is a case of good planning and good football sense on the part of the FA.
"It would be great to have the FA Cup Final back in Cardiff one more time, and this news is testament to the Millennium Stadium's success in hosting the past five FA Cup Finals. Football fans, and everyone involved in the game, can rest assured that we will deliver another fantastic day should we get the green light."
GB7s women left their England base to train in Wales this week. Olympic Games hopeful Rachael Burford gives WRU TV's Graeme Gillespie her thoughts on Welsh teammate Jasmine Joyce - a 'one touch wonder'
The GB7s women's squad is currently training at Wales' Centre of Excellence where assistant coach Richie Pugh tells WRU TV's Graeme Gillespie some 'tough calls' will have to be made when it comes to finalising the 12 spots for Rio's Olympic Games.
Wales U20's Billy McBryde is looking forward to starting his first game against New Zealand this afternoon in the World Rugby U20 Championship where his side are looking to gain revenge from last week's pool defeat to the Kiwis.