Brazilian carrier TAM Airlines is shifting its operations at Heathrow from Terminal 1 to Terminal 3.
The move takes place on May 27, taking the total number of airlines using the terminal up to 37.
TAM will continue to offer a daily service between Heathrow and Sao Paulo, connecting to 115 South American destinations.
It is estimated that 740 of the airline’s passengers will pass through Terminal 3 each day.
Business class passengers will have access to the Oneworld alliance partner British Airways’ lounge at Terminal 3.
UK and Northern Europe commercial director, Martin Modarelli, said: “We are delighted to announce our move to Heathrow’s Terminal 3 on May 27and are working hard to ensure a smooth transition between terminals for both our passengers and the travel trade.
“The new terminal will offer our passengers a great variety of shopping and dining options, as well as ensuring speedy connections and shorter distances between gates, all of which we hope will enhance the overall travel experience.”