Karl Lagerfeld was link once asked in an issue of Architectural Digest whether he was particularly obsessed with any design objects. His answer, as translated in this 2019 thread link on WatchProSite, cited the Royal Oak as a "fetish link object" for him and the watch he's "worn for 35 years." (For what it's worth, it appears the watch highlighted in the WatchProSite thread linked above is identical to the one Phillips is auctioning off; they have identical bracelet numbers.)