Aguilera is the real thing for Coke

Britney (left) and Christina are musical rivals

Pop star Christina Aguilera has signed a sponsorship deal with drinks giant Coca Cola.

The 20-year-old follows in the footsteps of music rival Britney Spears, 19, who last month signed a similar deal with Coke's world-wide rival Pepsi.

Coke is the world's most popular soft drink

When announcing the tie-up with Britney Spears, Pepsi said it was the biggest entertainment deal in the company's history.

Christina Aguilera, who had her TV break alongside Britney Spears when the two appeared on the Mickey Mouse Club TV show, will front a campaign in the US and South America, but not the rest of the world.

Signed deal

A spokesman for Coca Cola in the UK told BBC News Online: "Christina has signed a deal with Coca Cola in the States and South America.

"The details are still being worked out."

Christina Aguilera is a huge star in the US and in South America, where she has released an album entirely in Spanish.

Her breakthrough single in the US and Europe was the aptly-titled Genie in a Bottle.

Her 19-year-old rival has already appeared in her first Pepsi advert, shown during the Oscars.

The teenager was seen performing a rooftop dance backed by a giant Pepsi sign.

Other Pepsi promoters include British pop stars Robbie Williams, the Spice Girls and Boyzone, while in the US Janet Jackson and Ray Charles have both promoted the soft drink.