Maasai: Norton Invites Maasai Warriors to NY
The 40-year-old told the New York Daily News: "It literally is lions and elephants and giraffes and rhinoceros and things like that there - so if there's any ecosystem that's under threat on the planet that everybody has a sense of connection to, it's that one."
The trio will be racing in their traditional bright clothes and jewellery although they might swap their sandals for running shoes - but Oscar nominee Edward said he has no plans to follow suit.
"I think it would destroy me," said the star, who has already pulled a tendon in training.
Other celebs set to tackle the gruelling run this weekend include singer Alanis Morissette and former ER actor Anthony Edwards.
The marathon usually attracts several stars - in 2007 Katie Holmes took part, and was cheered on by her megastar hubby Tom Cruise and their daughter Suri.