(4 p.m. GMT) -- P&O Cruises has announced the preliminary line-up for "Ionafest", the music and entertainment festival at sea which will mark the naming of its new 5,200-passenger flagship Iona -- the largest ship ever built for the U.K. market. 

Grammy-award winning British electronic band Clean Bandit, four-time MOBO winning DJ Trevor Nelson, radio presenters Jo Whiley and Sara Cox and Blur's Alex James will perform during a seven-night Norwegian fjords cruise setting sail on July 4, 2020, after the christening ceremony on Southampton.

They will be joined by radio presenters Jo Whiley and Sara Cox, comedian and 2019 "Strictly Come Dancing" competitor Chris Ramsey, along with professional dancers from the show Amy Dowden and Ben Jones, and judge Motsi Mabuse. The floating festival's headline act and final line-up will be revealed closer to the date.

Throughout the week the performers will appear across Iona’s seven venues and passengers will be able to dance beneath the stars in Iona's SkyDome; an all new day-to-night glass-domed lounge and entertainment venue.

P&O Cruises' president, Paul Ludlow, said: "This really is an experience of a lifetime, a complete one-off. When has there ever been the opportunity to see to these award-winning artists?

“We're also so excited for our guests to be a part of the naming celebrations and we have made sure that there’s something for everyone to enjoy, all included in the price of a ticket to Ionafest 2020."

Iona launches in May next year, but will not be officially christened until July. The family-friendly ship will homeport in Southampton for its first season, offering cruises to the Norwegian fjords.

Bookings for “Ionafest” go on sale at 10 a.m. on Monday, December 9.