Tomorrow's Magners League showdown between Leinster and Munster at Lansdowne Road is set to break the record attendance for a match in the competition.

The biggest crowd to attend a Celtic League match to date stands at 15,327, set on May 14th this year at Cardiff Arms Park for the match between Cardiff and Leinster but ticket sales for tomorrow's game have already passed the 14,000 mark and the expectation is that the attendance will eclipse 20,000.

The West Lower, East Lower, South Terrace (which is seated) and East Terrace are all sold out, obliging the Leinster Branch to open up the East Upper.

That holds 7,000 tickets and if it too is sold out the branch will have to open the West Upper stand as well.

The North Terrace is closed due to the ongoing installation of bucket seats for the Republic of Ireland's European Championship qualifier at home to the Czech Republic next Wednesday.

The corresponding fixture last Christmas was a sell-out of just over 14,000 at the RDS but interest in this latest interprovincial rivalry has been heightened by their meeting in last season's European Cup semi-final.

Munster are expected to bring a significant travelling support, even though they only sold 500 tickets officially.

This is because tickets have been sold on the internet, aside from which the visitors will be backed by a huge contingent of Dublin-based supporters.

"We won't be short of red shirts anyway," observed the Leinster chief executive Mick Dawson.

The "Family Day" entertainment (including Canterbury Roadshow, live music, mini rugby and player appearances) starts from 6pm in and around the ground.

And Leinster Rugby have invited all past players and their partners to attend the launch of the Leinster Past Players Club in the Old Lansdowne pavilion from 6pm which is at the Havelock Square end of the ground.