"It hasn't really sunk in yet."
Payne played 38 times for Northland before heading to Ireland in 2011.
He qualified for Ireland under the three-year residency rule in 2014 and won his first cap against the Springboks in November of that year, quickly becoming one of Ireland coach Joe Schmidt's go-to players.
Payne stood out for Ireland in the final match of the 2017 Six Nations which bolstered his chances of making the cut.
He will be joined on the plane by Ulster teammates Rory Best (hooker) and Iain Henderson (lock/flanker). Payne said it would be good to be in familiar company.
"It's great for Ulster, there will be a few friendly faces on the trip. Those two have worked bloody hard over the last two years and it's good to see them be recognised."
Lions assistant coach Andy Farrell said Payne would be a real asset to the squad.
"He's a very experienced guy, who galvanises the backline, makes other people around him very comfortable," he said.
The Lions start their tour in Whangarei where they will take on the New Zealand Provincial Barbarians. Northland forwards Matt Matich and Josh Goodhue have been named in that squad.