Robert Joseph Reyes, 33, then forced the woman to lie on the ground and count to 200, with the threat: “If I see you get up, I’ll shoot you”.

But the woman recognised the armed robber as the husband of a school friend from wedding pictures posted on social media.

Reyes faced a sentencing hearing in the ACT Supreme Court on Thursday after pleading guilty to aggravated robbery.

Court documents said Reyes wanted money to buy heroin when he entered a Gungahlin video store about 11am on November 4 last year.

He threatened the sole staff member with a black coloured pistol – which the defence says was a replica firearm – and demanded money.

The female employee filled a shopping bag with cash before Reyes demanded she open a safe, saying: “Get me the f---ing fifties or I’ll shoot you in the head”.

He then fled with about $1100 and changed clothes in a nearby laneway.

The woman counted aloud to 83 before another employee arrived for work.

She identified Reyes on the social media pictures before police arrived.

The offender was arrested about 6.14pm that evening and has been in custody since.

At the sentencing hearing, defence lawyer Louise Taylor said her client accepted he faced a full-time stint behind bars for the raid.

But Ms Taylor said the firearm had been a replica and not capable of discharging bullets.

She said Reyes had been battling a serious heroin habit and a broken marriage when he took the gun to a drug deal on the morning of the offence.

He had been $30 short on the price for his daily hit of heroin and intended to rob his dealer, she said.

Ms Taylor said the deal went ahead at a reduced price and he impulsively robbed the store soon after to help fund his habit.

The defence argued Reyes now plans to study IT and had gone clean.

Reyes will be sentenced in May.