Last year's winner Chance Du Roy heads a field of 25 for the Betfred Becher Chase at Aintree on Saturday.
The Philip Hobbs-trained gelding will be having his first run since finishing finish sixth to Pineau De Re in the Crabbie's Grand National back over the famous fences in April.
Ballybough Gorta was fourth 12 months ago has another crack at this handicap over three and a quarter miles. His trainer Peter Bowen is also responsible for this year's Scottish National hero Al Co, who has to carry top weight.
Gordon Elliott's Troytown Chase winner Balbriggan heads a three-pronged attack from Ireland backed up by the Jim Dreaper-trained Goonyella and Tom Gibney's Lion Na Bearnai, winner of the 2012 Irish Grand National.
Sue Smith's Mr Moonshine could try to improve on his third place in this race last year.
Green Flag made an encouraging return to action when fourth to subsequent Hennessy Gold Cup winner Many Clouds in the Listed Colin Parker Memorial Intermediate Chase over two and a half miles at Carlisle.
Trainer Lucinda Russell is hoping for a big run.
"Green Flag is really well. I was delighted with his comeback at Carlisle over a trip that was too short and obviously the winner has gone on," she said.
"The step up in trip will definitely suit him. He has always been a very good jumper and should take to the course as the fences are very horse friendly now.
"I think he is on a reasonable mark and he has every chance."
Others in a highly-competitive line-up include Burton Port, Mendip Express, Mon Parrain, Our Father, Renard, Shakalakaboomboom and Oscar Time, who was second in the 2011 Grand National and fourth in 2013.
Andrew Griffiths of the sponsors said: "It's exciting to see such a big field declared for the Becher and it has all the makings of an absolute belter.
"Aintree is going to be packed to the rafters on Saturday and we're looking forward to a great day's racing."