Glen said: "We knew whereabouts we were sat, so we'd got an inkling that she may get to see him.
"But we never expected what happened, we just expected a little wave or 'aw' with his age.
"[Kylie] starts The Loco-Motion on the main stage, works her way over to the satellite stage, which is where we were stood."
Glen said Kylie then picked people from the audience to give roses to, "then she sort of focused on Reuben".
"She gave him a rose, and he gave her one back. His face lit up and she started a conversation with him," Glen added.
"The audience were watching on the big screen and 'oohing and ahhing' obviously, because he's a little boy who was smiling ear to ear.
"She was really engaging, she was fabulous. She'd obviously got an affinity with him, and then she sang the song to him."
Glen says Kylie initially spoke to Reuben about his clothing, as he was "bedazzled head to toe with Kylie signs and diamonds".
Reuben was also wearing specially made shoes for the event, featuring a diamond.
"He was stunned, he went quiet initially, which is unlike Reuben. He was just smiling with shock and surprise," Glen said.
"One of his first words was 'dam dam', which he was obviously trying to say 'Padam Padam'.
"He is a real fan as well, but we initiated that. He lit up all night."
Glen says as they were leaving the event, Reuben then got attention from other concert-goers.
"Because he'd been on the big screens everybody recognised him.
"People said 'you were really brilliant, weren't you Reuben', and he said 'yes I was'.
"We didn't expect all this," he said.