John Mayer Hangs with Childhood Pal James Blake

By Carlos Greer and Liz McNeil

08/22/2008 at 12:45 PM EDT

While his recent ex Jennifer Aniston did the town on Madison Avenue and the Met, John Mayer toasted tennis pro James Blake, his Connecticut classmate from Fairfield High at a Manhattan benefit for his charity, the Thomas Blake Cancer Research fund.

Honoring Blake's father, who died of cancer, the event was hosted by Men's Vogue and featured luxury watches.

"John is a watch guru. He tried on this skeleton watch, which is worth about $10,000, and even asked for our president's card," said Maurice Lacroix watch spokeswoman Fran Pennella.

Blake said of Mayer, "He's such an incredible musician. We're just so happy to see each other's careers grow."

"They're really supportive of each other," adds Blake's older brother, also named Thomas Blake. "Whenever they're in the same town, John is sure to go to James's tournaments and James is always at his concerts."

Said a partygoer: "He even offered music advice for our 4-year-old daughter. I asked him what would be the best instrument for her to learn, and he ... said, 'If she can learn piano, she can learn to play guitar, horns and the basic chords in music."