John Mayer may be known for his velvety, smooth voice and hit albums, but he's also a watch aficionado and prominent collector.
In fact, he loves watches so much that he's managed to get his "friends and colleagues to buy watches within the $8,000 range," the singer-songwriter revealed in a guest column for Hodinkee in 2012.
During a shopping trip a few years ago, Mayer convinced his friend Andy Cohen to spend big on a Rolex.
"I wanted to buy myself a watch to celebrate a new contract that I had just signed with Bravo," the "Watch What Happens Live" host told CNBC Make It at a Purina One event last week.
While Cohen didn't reveal how much he spent on the Rolex, he considers it as a "major splurge" outside the range of what he was thinking. "But I don't regret it," he said.
Mayer also got Kevin O'Leary to start investing in watches. Earlier this year, the "Shark Tank" judge told The Wall Street Journal that after talking to Mayer, he purchased a Patek Philippe Nautilus for $28,803 — and is now seeing gains of about $20,000 to $30,000 in value.
"Watch collections are going through the roof in value. Certain Patek Philippe Nautilus and certain Rolex watches and other makes and makes are beating the market by miles," O'Leary told the Journal.
In 2015, Mayer told The New York Times that his watch collection — which he stores in bank vaults — is valued "in the tens of millions." (That's about 25% of his estimated $40 million net worth, according to CNBC's "The Filthy Rich Guide.")
His past girlfriends have viewed his watch obsession as a "syndrome," Mayer admitted to the Times. "I spend probably as much time thinking about or diving into watches as I do anything else," he added.
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Disclosure: CNBC parent company NBCUniversal owns Bravo.