Various Twitter users noticed that the 92-year-old monarch -- stylishly dressed in a periwinkle blue coat with a matching hat and blue-and-yellow floral dress -- was waiting by herself for much longer than expected, and at one point took out her watch to check the time.
"Oh dear, she just looked at her watch. The Queen does NOT like tardiness," reporter Patricia Treble wrote alongside a screenshot of the queen holding up her arm and pointing at her watch. The gesture was also captured on camera and posted by another user on social media.
The queen then led President Trump to inspect the Coldstream Guards, one of Britain's oldest army units. The moment was quite comical as Trump kept walking, then stopping, not noticing where the queen was.