Only 14 months have passed since O'Sullivan resigned as Ireland head coach after seven years at the helm.

A new regime was called for and Kidney, having won two Heineken Cups with Munster, enjoyed a dream first season in charge - first securing a second seeding for the 2011 Rugby World Cup draw and then ending a 61-year wait for the Grand Slam.

The Cork-born pair's paths have criss-crossed over the years, most notably between 2002 and 2004 when Kidney was assistant coach to O'Sullivan in the Ireland set-up.

Kidney was quick to praise the efforts of his predecessor when Ireland lifted the RBS 6 Nations title in March.

Appointed as USA coach in March, O'Sullivan has been assembling a squad for Tests against Ireland and Wales (June 6), the Churchill Cup tournament and most importantly two Rugby World Cup qualifier matches against arch rivals Canada on July 4 and 11.

Pleasantries are sure to be exchanged, particularly between O'Sullivan and the more experienced Ireland players like tour captain Rory Best, but the new American supremo will adopt a business-like approach for the Setanta Challenge Cup

"It will be a big ask for us to win those games (against Canada) but it would be great if we could because it would put us directly into the Rugby World Cup. So it’s really something to work towards," he said.

"It's very important for us to get these games against Ireland and Wales. They’ll be tough games and it will be exactly what we need to get our heads set for the World Cup qualifiers.

"So they’re of huge value to us in that respect and they will give us a good indicator of where we are in terms of our preparations."

O'Sullivan's preparations have been hit by player withdrawals. Thirteen players are unavailable, including last year's captain Todd Clever and experienced campaigners Paul Emerick and Kort Schubert.