One of Pepsi's Super Bowl commercials will have nothing to do with soda - and that should terrify Coke

Bottled water - not soda - is taking center stage in PepsiCo's war against Coca-Cola.

The beverage giant bought a 30-second Super Bowl ad to debut the company's new premium bottled water brand, "LIFEWTR," The Wall Street Journal reported Tuesday.

It's an unconventional decision for a company whose most notable Super Bowl ad in 2016 was for Mountain Dew. However, as consumers move away from sugar-sweetened beverages, bottled water is becoming increasingly crucial to companies like Coca-Cola and PepsiCo once known almost exclusively for their name-brand sodas.

Bottled water sales have more than doubled in the US in the last 15 years, with Americans buying 11.7 billion gallons of the beverage in 2015.

Coupled with slumping sales in the soda industry, experts anticipate bottled water consumption to soon beat out soda consumption in the US - if it hasn't already.

Consumption of water sold by Dasani, which is owned by Coca-Cola; Aquafina, owned by PepsiCo; and Poland Springs, owned by Nestle increased in volume from 6.5% to 11.4% in 2015. For comparison, the amount of Coca-Cola consumed by Americans dropped 1% by volume, while consumption of Pepsi dropped 3.2%.

While a Coca-Cola spokesperson told The Wall Street Journal that while the company isn't planning on running Super Bowl ads for its bottled water brands Dasani and Smartwater, it is launching new ads for the brands in a few months.