Cox teamed up with Gerald Mosse for success with Reckless Abandon in 2012, while 12 months ago Adam Kirby steered Tis Marvellous to success.
Despite being a Group Two winner already, Heartache escapes a penalty in France but that has worked against stable jockey Kirby, who is unable to get down to the weight of 8st 12lb.
That means Mosse steps in for the ride, and Cox believes she might have even improved since her Ascot win.
"This is a race we've been looking at since she won the Queen Mary," he said.
"Although she's taking on the boys she does get a very handy sex allowance and also escapes a penalty for her Ascot win.
"Taking that into account, on the ratings she comes out very well and it just makes sense to run her in this without a penalty rather than take on fillies with one.
"Another bonus of running in this is that she's only stepping up in trip half a furlong rather than going up to six straight away.
"I think she's continuing to blossom and I'm looking forward to it.
"I'm not sure she'd ever want the ground too soft, but she is by Kyllachy. On what we've seen so far, though, she'll be at her best on quick ground."
Richard Hannon won the race in 2014 and 2015 with Kool Kompany and Gutaifan respectively and this year calls on De Bruyne Horse, who had been expected to run in the Super Sprint at Newbury instead.
The Middleham Park Racing-owned colt has not been disgraced upped in class since winning the Woodcote Stakes at Epsom.
Tim Palin, racing manager for Middleham Park, said: "We originally were heading to Newbury for the Super Sprint, but when this race looked like cutting up it looked the better option.
"At the end of the day it's a Group Two and the lure of that, plus it's over five and a half furlongs, proved too much.
"There's 20 runners over five furlongs at Newbury and that might not have suited, this is much more like what he's been doing.
"The ground won't get too quick, the emphasis will be a bit more on stamina and the owners will have a great day out.
"We won it a few years ago with Kool Kompany."
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Leyburn trainer Karl Burke is also represented through Unfortunately, who has had a run in France when second in a Listed race.
"He's a very nice horse and we're putting a visor on him for the first time," said Burke.
"It's obviously a very good race with Heartache and Frozen Angel in there. Our horse has a bit to find, but I wouldn't be surprised if he runs a big race."
As Burke mentioned, Tom Dascombe's speedy Frozen Angel also travels with home-based High Dream, and Ipompieridiviggiu from Italy completing the field.
