Cameron Diaz and Justin Timberlake Become African Vets on Trippin'  5/25/05

Celebrity couple Cameron Diaz and Justin Timberlake turned veterinarians on a recent trip to Africa when they teamed up with Frankfurt Zoological Society officials to vaccinate dogs and collar a lion.

The sweethearts were shooting an episode of Diaz's MTV travel show Trippin'

in Tanzania with pals Jimmy Fallon and Talib Kweli (corr) when they were invited to a Masai village in the Serengeti Reserve to inject their pets.

Diaz explains, "In 1994, an outbreak of canine distemper killed over 1,000 of the Serengeti's lions.

"Since then, one of the ways the FZS has been working to prevent a similar incident is by vaccinating the dogs in the area."

The celebrity quartet then risked life and limb when they helped take blood samples and a dental mould from a snoozing lion.

The stars had to replace batteries and a collar around the lion's neck, after it had been tranquillized, and then carry out routine tests on the beast.

It wasn't all dangerous work for the foursome - they spent the sunset of one day singing along to Toto's hit Africa on a rock in the middle of the Serengeti.