An estimated 10,000 Irish race fans will throng into a normally sedate Cheltenham today as the famous three-day racing festival gets under way.
The first-day feature is the £300,000 Smurfit Champion Hurdle, where the J.P. McManus-owned Like-A-Butterfly is the main Irish hope.
Over £2 million will be bet on the big race on the course, and millions more in betting shops throughout Britain and Ireland.
It's predicted that over £40 million will be bet at the track over the next three days.
Yesterday, the airports were full of race fans making the annual pilgrimage to the Cotswolds.
Security will be tight at the venue, especially on Thursday when Queen Elizabeth will attend for the first time since 1951 and present the Cheltenham Gold Cup.
Beef Or Salmon is the big Irish hope for that race, but he is one of some 80 Irish-trained horses who are running over the three days' racing.
Other star names in the visiting team are the Champion Chase favourite Moscow Flyer, and Limestone Lad, who runs in Thursday's Stayers Hurdle.
The bookmakers generally believe the Irish will have four winners over the three days. The best previous total for the Irish was seven in 1977 and 1996.
However, many bets will not be made until just before the first race at 2 p.m. this afternoon because of uncertainty about ground conditions.
"Good" with "good to soft" patches was the verdict yesterday, but there is rain forecast overnight for the area.
That would be a huge boost for Like-A-Butterfly's chances. She will be ridden by Istabraq's old jockey, Charlie Swan, who is the most successful rider at Cheltenham.
Swan has won 17 races at the festival, four more than his British-based rival Tony McCoy.
Today's first race is the Gerrard Management Supreme Novices Hurdle, where the Irish are expected to start with a winner.
Back In Front is a warm favourite to win for the Co Tipperary-based trainer Edward O'Grady.