Rap mogul Jay-Z is a man on a mission —several missions.
There’s the record label.
The new “Kingdom Come” CD
The Nets.
The 40/40 Clubs.
The clothing line and sneakers.
The Hewlett Packard Commercial.
The beautilicious girlfriend, Beyonce.

And now the MTV documentary “Diary of Jay-Z: Water For Life,”� which follows the rap star through Africa where children have to walk miles for water and play near open sewers in an Angolan slum. The show is part of the rapper’s partnership with the United Nations and MTV to get young people involved in the world's water crisis.

"I was looking for a cause to attach myself to," said Jay-Z at his documentary screening held at the United Nations.

Jay-Z, whose real name is Shawn Carter, said he decided on water "because it's the most basic need." MTV film crews followed Jay-Z while he visited children living without clean water in Angola and South Africa during his worldwide tour this fall. The documentary combines the children’s stories with startling statistics: According to the film, 1.1 billion people have no access to clean drinking water, and more than 4,000 children die every day from diseases related to the problem.

During a recent interview on the Steve Harvey Morning Show, Jay-Z said his upbringing in a Brooklyn housing project was more like paradise than the hood compared to the shantytown he visited in Africa—an experience he said was eye-opening.

In Angola , 37-year-old Jay-Z helped a schoolgirl lug a 20-liter container of water to the one-room shack—the rapper said it was about “the size of a jail cell”—she shares with six family members. The family has to pay a neighbor who has running water to fill the container twice a day. They make do with that even though the average person needs at least 20 liters a day for basic needs.

Jay-Z then followed the girl, Bela, to school past open sewers, and watched teenagers retrieve a basketball from black water, rubbing it off before resuming their game.

"You can't even take a deep breath," he said of the smell.

A visit to a village in South Africa was more uplifting. Jay-Z donated a "play pump" that spared children a grueling trip to a water hole. The devices are a sort of merry-go-round that pump water from a well into a storage tank.

"So many people that I've seen can't get clean water. It's a crime," he says at the end of the documentary. "I'm on a mission, and I will not forget."

Jay-Z, who recently came out of "retirement" to record his new CD, "Kingdom Come," told the audience he would donate the proceeds from an upcoming concert in New York to Water for Life, the U.N. initiative dedicated to meeting a U.N. goal of reducing by half the number of people without safe drinking water by 2015.

The documentary is just one part of Jay’s life; he recently completed his well-publicized, whirlwind one-day tour that saw him give seven 30-minute concerts in seven different cities in less than 24 hours.

The rapper and Def Jam Records president, whose return to the recording fold was cemented with the release of his new album, "Kingdom Come," last month, launched the Cingular Music-sponsored performing marathon, dubbed "The Jay-Z Hangar Tour," as a splashy re-entrance to the career he left following the release of 2003's "The Black Album," which the rapper hailed as his last.

"I'm crazy," he told MTV News. "I'm trying to bring some excitement back to the game."

The rapper hit seven cities on the jaunt, which kicked off with a 6 a.m. show in Atlanta, and then continued in Philadelphia, Washington, D.C., New York, Chicago, and Los Angeles. He ended up in Las Vegas a little less than 24 hours after the tour kicked off.

Jay-Z’s estimated worth is around $320 million, and he was recently included, along with B, on Time magazine's list of the 100 most influential people