The former Take That star and actress Ayda travelled to the country following a devastating 2010 earthquake, but were left fearing for their lives during the four-day trip after being ambushed by bandits.
Speaking on his "Postcards from the Edge" podcast, Robbie said, "I got threatened to be beheaded in Haiti. We were going out there to help. I was like, 'Should we go to the next street then?' and looking back, it was scary."
Ayda agreed, adding, "I was with you, I too was being threatened to be beheaded as well."
The couple travelled to Haiti with Unicef for an urgent appeal to help those who had lost their homes during the earthquake and, while the incident was scary, the "Candy" singer confessed that seeing the children who had suffered during the disaster made him want to become a father.
"When you go to somewhere like Haiti, it does make you feel like you want to help," he reflected. "It's awful what has happened. Working with kids has made me want to have them."
Robbie and Ayda are now parents to daughters, Theodora, aka Teddy, seven, and Colette, aka Coco, 21 months, and sons Charlton, five, and Beau, four months.