The Duke of Sussex delivered the opening speech at a virtual global summit for his ecotourism project Travalyst in the early hours of Thursday morning.
He began speaking at midnight LA time (8am UK time) via video link, urging the travel industry to "build back better" after it was rocked by the coronavirus pandemic.
But just a few hours later, he himself was being rocked – by a 4.2 magnitude earthquake that had Hollywood scrambling in fear.
Omid Scobie, ABC News royal contributor and author of the upcoming biography Finding Freedom, said Harry "would definitely have felt it".
The online travel conference was Harry's first public appearance since the publication of some scandalous extracts from Finding Freedom.
It's unknown how long he stayed up for after he finished his speech, but he was probably asleep when the quake struck at 4.29am local time, only to likely be woken up again by the violent shaking, Scobie said in the latest episode of The HeirPod.
"Not only did he head up this summit around midnight his time in LA so that as many participants could join as possible, there was also a part two at around 8am UK time and it was in middle of that, at around approximately 4.29am, that an earthquake struck LA," he explained.
"It would no doubt have been felt by the Sussexes, so I'm sure some sleep was much deserved by the Duke after that."
There was no report of damage or deaths in the quake but approximately 60 smaller aftershocks followed the first big shake.
A number of LA-based celebrities took to social media to say how frightened they were by the quake.
"Wow that felt much bigger than a 4.5 earthquake. So scary! Sneakers and my flashlight by my bed," she added.
Harry launched Travalyst last year with the aim of promoting more sustainable ways of travelling as well as ensuring local communities see the economic benefit of tourism.
"Travel has the unparalleled power to open people's minds to different cultures, new experiences and to have a profound appreciation for what our world has to offer," he said in a statement in September.
"As tourism inevitably grows, it is critically important to accelerate the adoption of sustainable practices worldwide; and to balance this growth with the needs of the environment and the local population.
"Bringing companies, consumers and communities together is our best chance to protect destinations and ecosystems for future generations."