The Irishman played twice for the Lions on the 2005 Tour of New Zealand and will look to use that experience to full effect on the sidelines this time around.
Easterby was announced as one of Farrell’s Assistant Coaches alongside Richard Wigglesworth, John Dalziel, Andrew Goodman, and John Fogarty.
Easterby joins forces once more with Farrell, having been a key part of the Ireland set-up as defence coach in recent years.
He most recently worked as interim head coach in the 2025 Guinness Men’s Six Nations, where he led Ireland to the Triple Crown.
Easterby said: “It’s incredible to be part of the Lions coaching team and this is a very proud day for me and my family.
“It doesn’t get any better than a Lions Tour. I was lucky enough to Tour with the Lions 20 years ago. It’s been a long time between gigs, but it is an exciting time and I am looking forward to getting stuck in.
“To Tour as a player and now as a coach, knowing the group of players that we have the potential of working with, is something that I can’t wait to get stuck into.
“A Lions Tour also gives you the opportunity to work with people you haven’t before.”
Easterby represented Ireland in 65 Tests as a player, alongside a club career that saw him represent Leeds Tykes, Llanelli and Scarlets.
He made his Ireland debut in 2000 and captained his country in 2005. The same year also brought his pair of Lions Test caps, with the back rower scoring a try in the second Test.