The duo further bolster the options available to manager Brett Whaley as the Tulips ramp up preparations ahead of the 2022/23 Pitching In NPL Midlands Division season.
Apindia Gille, 26, started his career with Belgian side VC Dilbeck.
He went on to have spells with White Star Brussels, KV Mechelen, RFC Wetteren, RFC Wallonia Walhain and more recently Corby Town.
The second new face to commit to the club is Hilliard, who began his footballing career at Kings Lynn.
He finished last season with Dereham Town after making a previous loan spell permanent.
“I’m delighted to make two new additions and to have them involved early in pre-season,” Spalding boss Brett Whaley said. “Both have looked really good in training and add something different.
“We have healthy competition for places throughout the team and the players are reacting well.”
Photo credit: Kings Lynn Town