A screenshot of Burger King's Twitter account. (Twitter)

Burger King's official Twitter account appears to have been hacked Monday -- instead of promoting the Whopper, it's promoting for McDonalds.

At around 12 p.m. EST, Burger King tweeted "We just got sold to McDonalds! Look for McDonalds in a hood near you."

The avatar for the Burger King Twitter account changed to the McDonalds golden arches with a red background, the name changed to McDonalds, and the background photo on the Twitter homepage was replaced with a photo of McDonalds chicken nuggets and fries.

The apparent hacker has referenced hacker groups Anonymous and LulzSec in the tweets, and the hack seems to be linked to Twitter user @DFNCTSC, who has not tweeted yet.

The account was still under hacker control after about an hour.

Feb. 18 is Presidents' Day, a national holiday in the U.S.