The first of its new Celestia trains will enter service in 2031, becoming the first double-deckers to operate in the UK and via the Channel Tunnel.
The 200-metre-long trains will be able to operate across all five countries served by Eurostar, and also to its planned new destinations Geneva and Frankfurt.
Alstom will build the new Celestia trainsets, named by members of the Eurostar team, which will increase seat capacity per train by 20% to 540, subject to final design specifications.