There are a lot of celebs who do The Hair Club for Men thing.

They put down a mesh-like netting. The next step is that they fill in all the little holes in the mesh with hair. Lastly, they tie it to the hair on both sides of the head.
The gross part is when you have to go back for
'servicing.'They remove it (it starts to move and slip as the real hair on both sides of he head grows) and they scrape all of the 'cheese' off the head. This is all the dead skin cells, dandruff, and sweat buildup and such.
GROSS.

They clean the hair attachment (fancy words for rug) and reattach it. One has to go for 'servicing' about four times a year on average. Some go every month.
Charlie Sheen, Emilio Estevez, Chuck Norris, Nicolas Cage, John Travolta, Tommy Lee Jones and Brenden Fraser are just a few of the celebs who wear them.
I remember back when that Sy Sperling guy was being interviewed on some show. It might have been Carson when he was still with us. Anyway, he said that the general public would be surprised how many celebs wear his 'hair system' or something similar from a rival company.