Dujardin, 30, and Valegro won individual and team dressage gold for Britain at London 2012 and have since won World and European titles.
But, she says, the Olympics in Brazil next summer will be the horse's last.
"This will be Valegro's retirement after Rio so I want to go out there and want to enjoy every last minute," Dujardin told BBC Points West.
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Dujardin partnered Valegro to victory in London as the two performed to movie themes including The Great Escape and Live And Let Die.
And the Gloucestershire rider says she is hugely excited at the prospect of defending her title, while admitting the Games in Brazil represents a huge logistical challenge.
"He's got to stay fit and healthy and get ready for the flight," she said. "It's a 16-hour flight and he needs to acclimatise.
"I'm really, really excited heading towards Rio. We get to go out in February and have a look around and fingers crossed it all goes well.
"Hopefully it won't be too hot, it's their winter time so high 20s."
Dujardin also says she will not let the pressure of being Olympic champion affect her.
"I just take it all on board," she said. "I try not to let that all bother me. Riding Valegro always makes you smile so I enjoy it."

As well as allowing robots to quickly respond to potential damage to their systems, it could also protect humans who are increasingly working alongside them.
The scientists plan to base the system on "insights from human pain research".
To test it, they fitted a robotic arm with a fingertip sensor that could detect pressure and temperature.
The researchers, from Leibniz University in Hannover, are developing a system that would allow a robot to "be able to detect and classify unforeseen physical states and disturbances, rate the potential damage they may cause to it and initiate appropriate countermeasures, ie reflexes", they explained.
Just as human neurons transmit pain, the artificial ones will pass on information that can be classified by the robot as either light, moderate or severe pain.
Researcher Johannes Kuehn told IEEE Spectrum: "Pain is a system that protects us. When we move away from the source of pain, it helps us not get hurt."
Teaching robots about a range of stimulus is important, robotics expert from Cambridge University Prof Fumiya Iida told the BBC.
"Getting robots to learn is one of the most challenging things but is fundamental because it will make them more intelligent," he said.
"Learning is all about trial and error. When a child learns that falling over causes pain, it then learns to do it with more skill."
Double Olympic champion Charlotte Dujardin says her horse Valegro will retire after the Rio Games in 2016.
[NEXT_CONCEPT]
Researchers from Germany are developing an artificial nervous system aimed at teaching robots how to feel pain.