Former Wasps and Wales scrum-half Rob Howley will coach the Barbarians backs ahead of their match against New Zealand at Twickenham on 4 December.
Howley won two trophies with Wasps at Twickenham last season
Howley, forced to retire with a wrist injury earlier this month, will work with Baa-Baas head coach Bob Dwyer.
"Rob has an outstanding pedigree and I'm looking forward to working with him and hearing his ideas," Dwyer said.
"This is my first coaching role and to be facing the All Blacks at Twickenham is a huge challenge," Howley added.
Howley played nine time for the Barbarians during his career, including against New Zealand the last time the sides faced each other in 1993.
"It was an unforgettable experience," added Howley, who also captained the invitational side at Cardiff's Millennium Stadium in 2001.
Howley was immediately tipped for a coaching role with the Cardiff Blues on his retirement, but has not made any firm decisions yet.
"I'm still reviewing my options since retiring but I would like to move into coaching and this appointment is a positive step forward for me," he added.