Owen Farrell will find himself on the opposite side to his father for the first time when Six Nations champions England bid for a record-breaking win against Ireland in Dublin on Saturday.
Victory at Lansdowne Road would give England a 19th successive international win, breaking the record for a 'tier one' or leading rugby union nation they currently share with world champions New Zealand.
It would also mean that England, who have already retained the title with a week to spare, became the first team in the Six Nations era to complete back-to-back Grand Slams.
But now England goal-kicking centre Owen finds himself on the opposite side to his father and Ireland defence coach Andy Farrell, who held a similar post with England until he left following the team's first-round exit at the 2015 World Cup.
Farrell junior, however, said the only member of the family for whom this was a problem was his mother, Colleen.
According to her son, the ideal outcome for Mrs Farrell was a 3-0 England win, with Owen kicking the lone penalty.
"We don't really joke about it. It's not like he's playing the game, there's only one of us playing in it and he's obviously got a coaching role," Owen said.
"I think the only person it will affect is my mum, not us. She just wants everyone to do well. She wants 3-0 England I think!"
Farrell, once renowned for goal-kicking and defensive skills, has become a genuine playmaker as he demonstrated with the quality of his passing in the 61-21 rout of Scotland at Twickenham last weekend, a match where England scored seven tries.
Asked if his father would have come up with a plan to counter his attacking threat, Owen said: "I guess we'll see...We don't speak to each other every day. We speak to each other what I would say is the normal amount, as any family would.
"We chat a bit of rugby, but we also have general chat as families would."
England coach Eddie Jones had no fear important tactical information may have inadvertently leaked out to the Ireland camp during a family conversation.
"They've probably been talking about rugby probably since Owen was big enough to sit at the table," said Jones.
"I think they're both mature enough to get on with it this week. Neither needs any more motivation to do well. They're Farrells -- I think that sums it up," the Australian added.