When former champion Irish rider Johnny Murtagh came calling, Steven Arnold had no hesitation in taking the ride on Royal Diamond in the Melbourne Cup.

Although Royal Diamond is the longer priced of the two Murtagh-trained runners, Arnold is buoyed by the fact the 3200 metres will be ideal for the gelding.

Mutual Regard, to be ridden by Damien Oliver, is at $11 while Royal Diamond is one of the outsiders at $81.

"Johnny was a great jockey and someone to listen to," Arnold said.

"He's happy with both horses and is confident that they'll run well."

Arnold partnered Royal Diamond in a gallop at Geelong in preparation for the Melbourne Cup.

He said he felt in really good shape and if he was to bring his best form he would be right in the mix.

Arnold has studied replays of Royal Diamond and said the nine-year-old had good speed from the barriers and should be up on the pace.

"I don't know if he'll be in front but it looks like he's pretty good from the stalls," Arnold said.

"I'll be a bit positive through the first two furlongs (400m) and get a spot and be in a position where he can use his strength a bit."

He said if the tempo was moderate he would up the ante about the 1200m and try to take the sprint out of the legs of those back in the field.

Arnold has had six rides in the Melbourne Cup with a best finish of third aboard So You Think in the 2010 Cup won by Americain.

He said Royal Diamond was a different type of horse from So You Think.

"So You Think didn't quite run out the two miles but this horse looks a more dour type and should run it out," he said.