When you're James Cameron, the normal birthday party celebration just doesn't cut it.

The director took to Russia's Lake Baikal today to descend more than 5,200 feet in a submersible; adding, however, that if there's bad weather, he'll be "getting drunk with the Russian crew in the port."

Lake Baikal is both the oldest (25 million years) and deepest lake in the world. It is home to more than 1,700 species of plants and animals, two thirds of which can be found nowhere else in the world.

While it's easy to speculate that Cameron is looking for a little inspiration for the planned "Avatar" sequel (hinted to focus on Pandora's undersea world), it's also a passionate hobby for the director going back to initial filming for the film "Titanic".

"I was hooked," he wrote in a 2004 Wired article, "infected by the deep-sea-exploration virus. After the success of the movie, I found myself less interested in Hollywood filmmaking and more interested in the challenges of deep-ocean photography and exploration."

According to MTV, Cameron will indeed bring that passion to next chapter of the "Avatar" universe — but he's quick to make a distinction between work and play. "I think what we should do there is — because we'll have to have characters that are in and under the water — is that we should actually capture them underwater," Cameron said. "It's not the same as going diving, but I like to keep my diving, which I do for pleasure, separate from work.

"Diving for shooting a movie is work," he added. "Diving for exploration is a gas. I like to keep my peas and carrots separate."

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

James Cameron to celebrate birthday deep under water
'Avatar' director to descend 5,200 feet in world's deepest lake.