The 24 year old, who made his Australian debut in 2012 against Argentina and has gone on to win 13 further caps since then, will join a roster that already includes Irish internationals Devin Toner and Mike McCarthy. Douglas will join Leinster once his Australian Rugby Union contract expires later in the year.
Ahead of his arrival Kane spoke to leinsterrugby.ie and spoke of his excitement. "It's a big decision but one which I am very excited about.'
"I've had plenty of time to weigh lots of things up and the time is right for me and my partner to experience something new and something totally different. We are heading for a new challenge in life and that's what excites us."
While he is looking forward to joining up with the rest of the Leinster squad in the new season he also acknowledged that there is still rugby to be played at home.
"Leinster is a massive club in Europe with a proud tradition and I'm really looking forward to doing my bit to add to the team once my commitments are done here in Australia"
Coach Matt O'Connor welcomed the addition of the young lock, "we are delighted to be able to formally announce Kane's signing. For a young guy he already has a wealth of rugby knowledge and experience under his belt and we also feel that he has the right character to succeed at Leinster.
"We can also formally confirm Leo Cullen's role as our Forwards Coach effective 1st July. He will bring a huge amount to Leinster Rugby as a coach and will continue the excellent work that Jono Gibbes has done over the last six seasons. As a three time winning Heineken Cup captain he already commands the respect of the players and that won't change."
O'Connor also confirmed to leinsterrugby.ie that Richie Murphy has signed a new deal with the province as Assistant Coach, with responsibility for skills and kicking. Murphy will also be seconded on a regular basis to the Irish Rugby Football Union in a similar role.
Murphy joined the Senior team as Skills and Kicking Coach in June 2010 having previously worked as Rugby Development Officer and Elite Player Development Officer for the province.
"Richie has made a significant contribution to Leinster Rugby over a number of years. In his time with the Senior team in the last four seasons he has developed into a top class coach at this level and I look forward to continuing to work with him''
Finally Marco Caputo will be joining the Province as Scrum Coach. Former Australian hooker Caputo made a name for himself with the ACT Brumbies and closer to home with the likes of Clermont and Harlequins and played in five tests for Australia in 1996/97, scoring one try.
O'Connor concluded, "I've known Marco for a long time and have been impressed by the work he has been doing at the various clubs that he has coached. When you look at our squad we have a great cross section of experience and youth in the front row who have all developed under the tutelage of Greg Feek, and who are all eager to improve and challenge themselves further at the highest level.''
All three coaches will take up their roles from the 1st July 2014, while a confirmed start date for Kane Douglas will not be announced until later in the summer
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