The thing with good looking A-list celebrities is that they never seem to go bald in the same way the rest of us do. Beckham clearly seems to be thinning but the hairline is intact. My money is on the combination of an earlier FUE + concealer.
Honestly, I would be very surprised if not pretty much all of the big earning celebrities famous for their looks has done at least something, when starting to age. I mean if your "personal brand" is valued in hundreds and hundreds of millions and you have an entire staff managing your career, the pressure to mesure up to your public persona must be tremendous.