Armed police and the former Eastenders star, who played Grant Mitchell, were called to a Birmingham branch of McDonald’s, following reports a man had been seen brandishing a knife at another customer.

Ross Kemp was on duty with West Midlands police as part of a new crime show when they received a call about an incident in the fast-food restaurant.

The incident happened on Thursday afternoon after reports tensions had flared and a customer had pulled out a knife.

But when the officers arrived at the scene, the man had already left.

A West Midlands Police spokeswoman said: “We were called at 4.20pm to McDonalds, Bristol Road South, to reports a customer had pulled a knife on another diner following a disagreement.

“Officers, including the firearms unit, were sent to the scene. No arrests were made.

“Officers are still searching the area and checking local CCTV.

“Ross Kemp is currently spending time out on patrol with some of our officers.”

Twitter users flocked to the social media platform after they were shocked at spotting Mr Kemp in the area.

One user wrote: "Why is Ross Kemp in Northfield right now?!"

Another tweet read: "Have just seen Ross Kemp leaving Northfield McDonalds. Not joking. V bizarre."

Another said: “Lol Ross Kemp outside my local maccys.”

This comes after Ross Kemp was left deeply shaken on his new documentary Behind Bars: Inside Barlinnie after a particularly troubling interview with a sex offender.

The prisoner’s identity was hidden and his voice disguised for the talk with the investigative journalist, 53.

Shortly before speaking to a prisoner in the E Hall, where the sex offenders are kept separate from the rest of the prison population, Kemp admitted: “I’m not looking forward to going in.”

He spoke to one man who was serving time for downloading indecent images of children and found out he was a repeat offender.

At one point during the interview, Kemp asked the prisoner: “Do you think you can be rehabilitated?” The prisoner simply responded with a “no”.