In September, the Line Of Duty fan favourite devoted the accolade to his 89-year-old mother, who had then just recovered from coronavirus.
Speaking on stage at the GQ Men of the Year awards ceremony, Mr Dunbar thanked the BBC, Line Of Duty creator Jed Mercurio and his co-stars and “best mates” Vicky McClure and Martin Compston.
“But I’d really like to dedicate this award to my 89-year-old mother Pauline, who beat Covid last week,” added the 63-year-old actor.
Mrs Dunbar, who was herself a former actress, died “peacefully” on Saturday, according to a funeral notice.
Mr Dunbar spoke last year of his fears for his mum during the pandemic. Mrs Dunbar had Alzheimer's and lived in a care home in Northern Ireland.
While he was self-isolating at his home in north London, the Enniskillen native spoke about his worry for his mum amid outrage over the health department's treatment of Covid-19 cases in care homes in Northern Ireland and across the UK.
"I'm worried about her, I'm worried about those care workers, whether they're getting the personal protective equipment and when they're going to get tested - they're frontline workers,” he had said last April.
"We can see my mum and talk to her on WhatsApp, so there are positives, but it's a really vulnerable sector and the Government has to swing its focus on it."
Mr Dunbar has also previously spoken of how he believes he got his career talents from his mum, who loved singing and performing.
Her funeral will be held in Enniskillen on Monday evening.
“Beloved wife of the late Sean and loving mother of Adrian, John, Roisin, Christina, Liam, Madeleine and Moira,” the funeral notice continued.
“Very sadly missed by her sons, daughters, grandchildren, great grandchildren, sons-in-law, daughters-in-law, nephews, nieces, close friends and entire family circle”.