The riders are vying for the £100,000 jackpot with competitions which start tomorrow and run to Sunday.
The international riders have been confirmed as Roelof Bril and Jochen Munsterhuis from the Netherlands, Raephael Goehrs from France, Dirk Demeersman and Pieter DeVos from Belgium.
The British and Irish riders competing at the Show will be Conor Swail, Cian O'Connor, Billy Twomey, Harry Marshall, Shane Breen, Marion Hughes, Edward Doyle, Benny Kuenhle, Marie Burke, Joanne Sloan Allen, Anthony Condon, Trevor Breen, Robert Smith, Nick Skelton, Geoff Billington, Ellen Whitaker, William Funnell, Tim Stockdale, Ben Maher, Michael Whitaker and Mark Armstrong.
The Horse Show also marks the end of an era for a certain equestrian celebrity.
Mr Springfield is due to retire at Sunday's Grand Prix event. Mr Springfield's impressive track record includes several major wins such as the British Open, the Olympia Show, Horse of the Year Show as well as the Nations Cup at Hickstead, ridden by Olympian Robert Smith.
The Northern Ireland International Horse Show is not just about thrilling competing and top class show-jumping, there are a variety of display acts including Pignon and his dancing horses, the Cossacks death defying stunts, Crufts winner Kath and collie Spice.
For the glamorous fashionistas there is also the inaugural Ladies Day on Sunday in association with The Outlet with £250 worth of vouchers up for grabs for the best dressed lady, launched by our very own fashionista Miss Zoë Salmon.
Show President Joe Sloan said: "We are delighted with the calibre of equestrian talent who have signed up for the Show, it is testament to the Show that such Stars are lining up to compete. We are expecting top-class show-jumping as well as the very best in Pony Club games and equestrian displays which will make for superb spectating for all the family."