The pair struck up a close friendship during their time together at Mercedes, with Cullen playing an important role as Hamilton added four more world titles to his haul.
The compatriots have forged up a strong connection in recent months, with Armstrong hailing her impact despite the 24-year-old experiencing an up-and-down campaign so far.
Though enduring some difficult times on the track, Cullen is enjoying her role, and is thrilled to have the opportunity to take in new experiences.
Speaking on the IndyCar YouTube channel at this season's Firestone Grand Prix of Monterey - held at Laguna Seca in California - the 50-year-old admitted she was stunned after seeing the legendary circuit up-close.
“I’ve been here four days - but first impression, it’s incredible!” she explained.