George, 35, allegedly took part in the theft of thousands of pounds worth of jewels and a carjacking. He has been bailed until 20 August.
Herts police said in a statement to The Mirror: "A 35-year-old man from South Oxfordshire was arrested on suspicion of conspiracy to commit robbery on July 25. He has been released on police bail until August 20."
Three other men were also arrested and are currently on police bail.
George has one child, daughter Dylan-George, with Atomic Kitten star Kerry.
Kerry was reportedly unaware about the arrest, but she appeared to refer to the latest reports after tweeting a cryptic message: "We all have complete control over the things that we say but we have no control over how it effects others. Choose your words wisely. Morning."
She later added: "I got my Friday smile on! Have you got yours??"
Reveal have contacted Kerry's rep for comment.
The alleged incident took place just days before George is said to have moved back into the family home with Kerry following a brief split.
It was reported in early July that Kerry and George's marriage was on the rocks after she was said to have thrown him out of their home.
Try Reveal's digital edition on iPhone & iPad. Subscribe now & never miss an issue!