The first semi-final will kick off at 5.15pm on Saturday 16 April 2005, with the second semi-final following on Sunday 17 April at 4pm. The BBC and Sky Sports will each broadcast one semi-final live.
This is the first time that the Millennium Stadium has been selected as an FA Cup semi-final venue. With a capacity of 74,525, it is significantly larger than both Villa Park (42,602) and Old Trafford (68,210) which have hosted the semi-finals in recent years.
An FA spokesman said: "Taking the semi-finals to Cardiff will ensure that the semi-finals are played at a neutral venue and that the maximum number of fans are able to attend what are always great occasions.
"The Millennium Stadium has been a wonderful venue for the FA Cup Final since 2001, with a unique atmosphere for players and supporters alike."
Wales' national stadium has played host to 6 different clubs - Liverpool, Arsenal, Chelsea, Manchester United, Southampton and Millwall - in previous FA Cup Finals since the showpiece matches moved to Cardiff in 2001. Arsenal are the only team to have played multiple finals, making three appearances, though they are joined by Liverpool and Manchester United in having returned for FA Community Shield matches twice.
"The Millennium Stadium is delighted to welcome our friends from the FA to Cardiff for an extra two matches this season," said Millennium Stadium Chief Executive David Moffett.
"This is a wonderful accolade for the Stadium and Cardiff, to be asked to host more prestigious FA Cup matches and it is a further reflection of our growing reputation as a major event venue for world sport and entertainment.
"I'm also personally delighted that the chances of my beloved Spurs coming to town again have been increased, as now 'we' only have to reach the semi-finals!
"Indeed, it will be interesting to see if there are any new names to join the elite band of 38 Football League clubs that can say they have played here in either FA, Football League or UEFA competition.
"But whoever makes it through we look forward to two new magnificent occasions, whether we are welcoming new visitors to the Millennium Stadium or greeting the return of some old friends."
David Moffett takes penalties during the launch of the FA Cup
semi-finals at the Millennium Stadium
There have been 30 club football matches played at the Millennium Stadium since it was built in 1999, featuring 38 different Football League clubs, 1 Spanish, 1 Italian and 1 League of Wales club.
The Stadium has hosted 4 FA Cup Finals, 4 Community Shield matches, 4 Football League Cup finals, 4 sets of Football League Play-off Finals featuring Divisions 1-3, 4 LDV Vans Trophy Finals, 1 UEFA Cup clash and 1 'Cardiff Capital Challenge' invitation match
David Moffett's Tottenham Hotspur's only previous visit was as the losing side in the 2002 Football League Cup final to Blackburn Rovers. The other sides to figure at Millennium Stadium whilst playing in the premiership are Chelsea, Southampton, Bolton Wanderers, Middlesborough and Manchester City.
"These are magnificent events which require the highest standards of event management and organisation and the Millennium Stadium is, I'm sure, joined by the whole of Wales in being immensely proud hosts."