The two of them teamed up to help the British & Irish Lions to a series victory in Australia but Warren Gatland admits he is now hoping to make the most of any inside information he has gleaned from working with Andy Farrell.
England’s backs coach Farrell was a key cog in the Lions coaching set-up that helped the tourists to their first series win in 16 years.
However with Gatland Wales head coach and Farrell and Graham Rowntree part of Stuart Lancaster’s England staff the return to international rivalry was inevitable.
And with Wales and England drawn in the same Pool for the 2015 World Cup Gatland confesses he relished the chance to pick the brain of one of his main rivals.
“I made it, a little bit selfishly, it was a chance for me to bring in someone who I hadn't worked with in the past, in terms of Andy Farrell, who was well regarded by anyone who I spoke to,” he said.
“There was, I suppose, a part of me looking long term – knowing that Andy could do a good job – but also, if you are thinking you know what the World Cup pool is and knowing that we were going to have England in our pool, potentially it gives me a little bit of an insight into England and their preparations.
“That's a little bit of the cutting side of me. You don't admit those things and that's probably more of a reflective decision, saying what happens afterwards.
“There was no doubt that by us going on the Lions, we have given away, from a coaching set up and backroom staff, a huge amount of information, so it's always nice to get something back as well.”