Steffen, Olympic champion at both 50 metres and 100m freestyle in Beijing, mirrored her achievements at the World Championships in Rome last summer with Halsall claiming a surprise silver medal over two lengths.

Also racing for the Germans will be Paul Biedermann who shocked Michael Phelps by taking both his 200m freestyle world title and world record at the Foro Italico.

Biedermann also claimed Ian Thorpe's long-standing 400m freestyle world mark by 0.01seconds although he estimated his Arena x-glide suit was worth about two seconds over the eight lengths before adding they should be banned - which they now have.

A 35-strong Great Britain squad has been selected for the event on February 20-21 which as well as Halsall, features double Olympic champion Rebecca Adlington, Rome triple medallist Jo Jackson and Liam Tancock, world 50m backstroke world record holder.

David Davies makes his first competitive appearance in what is a seminal year for the Welshman who will decide after October's Commonwealth Games whether he will continue to compete in both the open water and the pool or just focus on the former.

Also competing will be world 4x200m relay bronze medallist Jazmin Carlin, double Commonwealth champion Caitlin McClatchey and world and Olympic backstroke finalist Lizzie Simmonds.

Highly-rated prospects Anne Bochmann and Aimee Willmott will join others like Georgia Davies and Jessica Dickons on the fringes of the senior team.

The British team enjoyed their first taste of head-to-head competition at December's British Gas Duel in the Pool in Manchester when a European select side took on the USA over 25m.

The event against the Germans at the Wales National Pool will again feature straight finals, with the first three in each race awarded points and the nation with the most points at the end of the weekend crowned victors.