Saints sign McCarthy as competition for Forster

The 26-year-old -- who signed a three year contract -- is likely to play second fiddle to England international goalkeeper Fraser Forster but should gain playing time as Saints are also involved in the Europa League. 

"We now have two quality English goalkeepers who have both represented the country at international level," said Southampton executive director of football Les Reed.

"I am confident that Fraser will soon be England's number one, and in Alex we have a young player who has already had a taste of the England senior squad, as well as excellent experience at Under-21 level.

"Alex is ambitious and will be pushing for a starting place every time he gets the opportunity, which can only be good for Fraser and a shining example for Harry Lewis and the younger keepers below."

McCarthy, who won three caps for the England Under 21 side, said he was looking forward to getting plenty of playing time for the first team.

"I'm over the moon to join a club like this. The club is known for producing young players and they've had successful seasons," said McCarthy.

"There's the Europa League to look forward to this season, so there's going to be a lot of games.

"With the stature of the club, I'm honoured to be here and I'm looking forward to getting working with everyone."

McCarthy, who had been at Palace for just a year, joins Danish international midfielder Pierre-Emile Hojbjerg, who cost a reported £12.8million ($16.6m, 15m euros) from German champions Bayern Munich and Nathan Redmond, a £10m capture from Norwich, as new arrivals during the close season.

Saints will also have a new face in the dugout as Frenchman Claude Puel replaced Ronald Koeman as manager after the Dutchman left for Everton.