Japan Airlines Co. said Thursday it will upgrade the seats in its Boeing 777-300ER jets starting next year in a bid to beef up its international competitiveness.

The new seats are scheduled to be installed from January on jetliners flying between Narita International Airport and London's Heathrow Airport, and later to other aircraft connecting to Europe and the U.S., the carrier said.

The new first-class seats can be turned into fully flat beds measuring 199.4 cm long and 84 cm wide, with a 23-inch personal monitor replacing the current 19-inch model, JAL said.

The 23-inch monitor will be used in business class as well. JAL for the first time will also put seats that become beds in business class. Fully flat, they will be about 188 cm long.

New seats in premium economy and economy classes will have more leg room, it said.

The airline, coming back from bankruptcy and scheduled to return to the Tokyo Stock Exchange next Wednesday, will also revamp its in-flight meals for first and business classes, collaborating with four famed chefs, including Michelin three-star chef Seiji Yamamoto.

As promised in the medium-term management plan to offer service that would thrill customers, this new service will be the core part in realizing that goal, JAL President Yoshiharu Ueki said.

"We couldn't invest adequately (to renovate our hardware) due to the situation that everybody knows," Ueki said.

"We've been trying our best to offset (the lack of the latest hardware) with human services. I'm really happy to finally offer these upgrades."