The star of hit show SAS: Who Dares Wins was fired from the British Army's elite regiment when his commander spotted him on the cover of Hello! magazine moonlighting as a bodyguard to Brad Pitt and Angelina Jolie.
Mark 'Billy' Billingham said he took a call from his furious commanding officer as he sat at the Hollywood couple's Chateau Miraval in the south of France.
He had taken a fortnight's leave from the Army to earn some extra money and do a favour for a friend.
After shouting a string of expletives, his SAS boss eventually calmed down and asked him whether after 27 years' service in the Army, his new job made him happy.
When Billingham - who is now the chief instructor on Channel 4's SAS: Who Dares Wins - replied that it did, his exit papers from the regiment were arranged.
Billingham, 57, first started off moonlighting as a bodyguard to supplement his meagre SAS wages.
Mark 'Billy' Billingham with the couple and their youngest child in New York in 2007
Billingham waits for Angelina Jolie as she gets into a car in 2007
He earned £10,000 a month – three times what he was earning in the military.
He also made the extraordinary revelation that other Hollywood stars' guards had been lying that they were also former SAS soldiers.
Speaking to an audience at the Forum in Bath, Somerset, about his experiences, Bellingham described a visit to the Hotel Du Cap-Eden-Roc in Antibes with the couple.
'Brad gives me the thumbs up that it is time to leave,' he said.
'I get up to walk through this hostile crowd of bodyguards. As I get up they are all smiling at me and pulling chairs out of my way.'
Billingham is now the chief instructor on Channel 4 's SAS: Who Dares Wins
Billingham, 57, would moonlight as a bodyguard for Pitt to supplement his meagre SAS wages
Billingham holds the hand of one of Pitt and Jolie's children as he walks with the star
Billingham is seen protecting Jolie and Pitt and their children during a family outing
After they left, Bellingham asked a fellow guard, who was a woman, 'What just happened then?'
He recalled: 'She said, "Well, I said to them all [sarcastically], why don't all you SAS guys have a beer with a sergeant major from the SAS?
'And they all went, "Oh, f***". That's when I realised that every one of these bodyguards [had been claiming] to be in the SAS.'
'But I was the only one that was. The big bear on the door couldn't even spell SAS.
'He was Italian. And this is the situation I was now in. Everyone I was meeting in the bodyguard community was reputedly in the SAS but not one of them were.'
Billingham previously told how it was 'great' working for Pitt and Jolie, who separated in 2016. Their divorce was sealed three years later.
They share children Maddox, Pax, Zahara, Shiloh, and twins Knox and Vivienne.
Speaking to Australian outlet Women's Day, he said his biggest concern was the safety of their children.
The mother and father hold two of their children in their arms with Billingham close by
Billingham with the couple during a glitzy outing. He was fired from the SAS for his second job
'The biggest concern for them was the kidnapping of the kids, it's all about money,' he said.
'Angie and Brad are very worried about who goes near the children.'
Billingham added that he was surprised by the pair's time management skills.
'The one thing that surprised me about working with Brad and Angelina was their time management, and how they had time to do everything from family life to work and to charity,' he said.
'I learned a lot of lessons from them, they learned a lot from me and the beauty of working together was the mutual respect.'
The former couple fell in love on the set of their 2005 film Mr. & Mrs. Smith, while Pitt was still married to Jennifer Aniston.
They married in France in 2014 after ten years of dating.
Their shock divorce was allegedly triggered by an incident between Pitt and his then 15-year-old son Maddox, on a family flight home from France.