Facebook Zuckerberg doesn't just wear any old plain grey Hanes t-shirt, though. His are special ordered from Brunello Cucinelli, and reportedly cost between $300 and $400.

So as honor to my past, I would wear the plain gray t-shirt to the Octagon. It was only fitting that the first Dan "The Beast" Severn t-shirt should be grey.

Mark Zuckerberg wore a boxy black T-shirt with a Latin phrase on it at the Meta Connect keynote. ... It's a notable departure from this former hoodie and plain-gray-tee uniform.

Rebel Wilson keeps it casual in plain grey T-shirt and figure-hugging trousers as she emerges from her hotel with messy hair and flustered smile. By AMY ROBERTS FOR DAILY MAIL AUSTRALIA .