1217 GMT August 16, 2018
Looking back over the events of 2017, the Queen says both cities' ‘powerful identities’ had ‘shone through,’ BBC reported.
The Queen will also praise the Duke of Edinburgh for his support, in the year of their 70th wedding anniversary.
She will spend the day at Sandringham with the Royal Family, including Prince Harry and his fiancé Meghan Markle.
It will be the first time someone who is yet to marry into the Royal Family will have joined its Christmas celebrations.
The Queen was absent from last year's Christmas morning service at the estate in Norfolk because of a heavy cold.
The Queen recorded this year's Christmas message to the Commonwealth a few days ago in the 1844 Room at Buckingham Palace.
Its main theme is the importance of ‘home,’ which she describes as a place of ‘warmth, familiarity and love,’ with a ‘timeless simplicity’ and ‘pull.’
On a table, alongside photographs of Prince George and Princess Charlotte, are two pictures of her with the Duke of Edinburgh, one of which was taken on their wedding day in 1947 and the other from their anniversary in November this year.
Prince Philip this summer retired from his program of public engagements, although he has continued to attend some events involving the Queen.
In the broadcast, the Queen also praises her husband's ‘unique sense of humor.’
The Queen is dressed in an ivory white dress by Angela Kelly, which she first wore for the Diamond Jubilee Thames River Pageant in 2012.
The Queen will say in her message: "This Christmas, I think of London and Manchester, whose powerful identities shone through over the past 12 months in the face of appalling attacks."
Five people, four pedestrians and a police officer, were killed in the Westminster Bridge attack in March.
In May, the Queen visited victims of the bombing at Manchester Arena, in which 22 people died. A suicide bomber struck as they left the venue following a performance by US singer Ariana Grande.
The following month, eight people died when three men in a van ploughed into pedestrians on London Bridge before going on a knife attack in nearby Borough Market.
Later that month, a man died when a hired van ran into worshippers near the Muslim Welfare House in Finsbury Park, north London.