Three’s company. Brad Pitt and Angelina Jolie’s former bodyguard, Mark Billingham, says that he practically ‘fathered’ the couple’s six children in a new interview published Sunday, October 16.

A former bodyguard for Brad Pitt and Angelina Jolie revealed today that the estranged couple feared their children would be kidnapped and held for ransom.

Mark Billingham, a decorated former British Army soldier from Walsall, spent nearly 18 months as head of security for the Mr & Mrs Smith stars and their six children.

And he has told of the painstaking measures they took to ensure they were safe, as well as the numerous run-ins with stalkers of the former A-list king and queen.

Opening up: Mark Billingham, pictured on Channel 4's SAS: Who Dares Wins, has spoken about working with celebrity couple Angelina Jolie and Brad Pitt and their children

Security: Mr Billingham is pictured (left) with the family at Chicago's Field Museum in 2007

Mr Billingham walks with Pitt and his children Zahara and Pax in Prague in May 2007

According to The Sun journalist Jen Pharo, Mr Billingham said: ‘The biggest concern for them was the kidnapping of the kids, it’s all about money.’

He added that the couple were extremely focused on protecting their six children – Maddox, 15, Pax, 12, Zahara, 11, Shiloh, ten, and twins Vivienne and Knox, eight.

Mr Billingham said Pitt, 52, and Jolie, 41, trusted him with the children so much that as he bonded with them, he ‘could take the kids anywhere I wanted to on my own.’

He also said that the former power couple were constantly uneasy about who would go near their children, to the point that they were mindful of security professionals.

Pitt walks with Mr Billingham and his children Maddox, Zahara and Pax in New York in 2007

Mr Billingham with Jolie, Pitt and children Maddox, Pax, Zahara and Shiloh in Chicago in 2007

Mr Billingham carries Pax into a school at the American Embassy compound in Prague in 2007
‘Even when I wanted to bring in extra people, they wouldn’t let any of those near the kids,’ he said.

The added guards ‘could look out for them from a distance but they couldn’t physically touch them’.

Mr Billingham spent so much time around the children, he said he felt like he ‘fathered them, basically.’

DailyMail.com has contacted spokesmen for both Pitt and Jolie. Representatives for Pitt have declined to comment.

Pitt smiles with Mr Billingham as he collects Zahara and Pax from a school in Prague in 2007

Constantly there: Mr Billingham spent so much time around the children, he said he felt like he 'fathered them, basically'. He is pictured with the family in Chicago in 2007

Careful: Pitt, 52, and Jolie, 41, were fearful their children could be kidnapped or held for ransom, according to their ex-bodyguard. They are seen here in February in Los Angeles

Defensive: Pitt and Jolie, pictured here in 2011 in New Orleans, were wary of security professionals being around their children, Mr Billingham said
Mr Billingham – who also has provided protection for Russell Crowe, Sean Penn and Tom Cruise – said he spent much of his time keeping Pitt and Jolie protected from stalkers.

He recalled a chilling situation that even reminded him of the murder of John Lennon in December 1980 at the hands of crazed fan Mark David Chapman.

‘Angie was filming in a crowd and everyone’s got smiles on their faces except for one guy: He looked angry,’ Mr Billingham said to The Sun.

‘A few days later we were coming off set and this guy came running down the road with photos to be signed.

An eye out: The couple was 'very worried about who goes near their children' throughout Mr Billingham's nearly 18 months as their security ace

Bonded: Mr Billingham said he felt like he fathered the children after spending plenty of time with them

Special connection: Mr Billingham said the couple and their children immediately took to him 
The security guard said that Jolie wanted to get out of the vehicle to do it but he denied her and instead got the photos himself and took them to her.

After seeing them, he said she was surprised how personal the snaps were.

Mr Billingham said when he confronted the man, ‘the guy ran off – [but] then reappeared days later near the hotel – so I [had] him arrested.’

He later learned that the man had been ‘following Angie all over the states.’

Mr Billingham also explained to The Sun that the Fight Club star needed more protection than the Maleficent beauty.

Scary: The ex-guard recalled a terrifying tale involving a stalker focused on Angelina, seen here in 2014 in Los Angeles 
‘People love her but hate him,’ he said. ‘You have to figure out a way of protecting them from all that. It was challenging, but interesting.”

Mr Billingham, who also has six children, said he eventually had to quit the job because he ‘lost direction in [his] own family life’ amid the endless hours keeping an eagle eye on the famous family.

‘I never had a private life – I was exhausted,’ he told The Sun, adding he still does occasional freelance work for the stars, who parted ways amid Jolie’s filing for divorce from Pitt last month.

Mr Billingham said: ‘In 17 months, I was only home for six weeks – it was just too full-on.’

Strange dynamic: The security expert said that while people generally like Jolie, there's some hostility toward Pitt. He added: 'You have to figure out a way of protecting them from all that'
Separately, Mr Billingham told The Times journalist Ben Machell how he operates, saying: ‘It’s mostly word of mouth. I’ll get a call from Angie.

‘She’ll say, “Hey Billy, I’ve got this thing in Baghdad. Can you come and help me out?” “Yeah, no problem at all.”

‘I’ll fly out to Jordan, meet her and the kids there, then take her to meet the UN. Just sort her out.’

He also spoke of lighter moments and that Pitt once played a practical joke, explaining: ‘It was Angie’s birthday and we were all sitting in a frigging Audi Q7.

‘I hadn’t been working with them long and suddenly Brad has locked the doors and farted and we couldn’t get out. He won’t have a problem with me telling you.’

Series two of SAS: Who Dares Wins starts on Channel 4 tonight at 9pm