Connections have confirmed that Darmouth will run in the Dubai Duty Free Legacy Cup at Newbury on Saturday before racing in Canada.
The four-year-old, who is trained by Sir Michael-Stoute, won the Hardwicke Stakes in June at Royal Ascot for the Queen on her 90th birthday.
A month later he finished third in the King George VI and Queen Elizabeth Stakes but he will now return after a short break.
Saturday's Group Three contest will be classed as a warm-up for Dartmouth, who is being primed for the Canadian International on October 16.
The Queen's racing advisor, John Warren, said: “He's a big, strong horse and he's in very good form. The intention is for him to run.
“It's been a while since the King George and hopefully this will be a nice blow-out for him and a good prep race. The Canadian International is a possible target for him, if he did well on Saturday.
“It is obviously not ideal the ground being as it is, but there are not many options for him and hopefully it will blow away the cobwebs.
“There is no substitute for a run.”
