James (left) joins from the Warriors

The 41-cap man, who has not played for Wales since 2002, joins the Parker Pen champions on the day he was called up by the Barbarians to face Wales.

James, 28, was out of contract at troubled Welsh region the Warriors.

Also joining Quins on two-year deals are Jeremy Staunton and Maurice Fitzgerald, while wing Joe Mbu has moved from Bath on a one-year contract.

I'm confident all four will make a significant contribution to the squad Harlequins chief executive Mark Evans

"We are delighted to welcome this group of players to the Stoop," Harlequins chief executive Mark Evans told the club's website.

"They range from the experienced international in the form of Dafydd James, through to the exciting potential of Joe Mbu, as we look forward to planning what we hope will be another successful season, including our return to the Heineken Cup.

"I'm confident all four will make a significant contribution to the squad."

Wales' summer transfers

James played all three Tests for the Lions in Australia in 2001, but fell out of favour with Wales' last coach Steve Hansen.

Warriors change battle plans

He had decided to seek a contract outside Wales before the recent moves that look likely to see the demise of the Warriors.

Staunton, 24, an Irish international fly-half and full-back, moves to the Stoop from Munster.

Tight-head prop Fitzgerald, 28, has been playing his rugby with Biarritz and is a former England A international.

The new signings provide fresh blood to a Quins squad that will see the summer departures of Pat Sanderson, Paul Burke, Chris Bell, Bill Davison, Rob Jewell, Matt Moore, Scott Bemand, Ben Willis, Laurent Gomez and Jason Leonard.