"We have conveyed to the Pakistan High Commission in London to fully cooperate with the (Sharif) family to bring back the body", Iftikhar Durrani, media adviser to the prime minister, told Arab News.
When Nawaz and Maryam Sharif left London for Pakistan in July, they knew they faced lengthy jail terms and would likely not see Ms Nawaz again.
"COAS expresses his grief and heartfelt condolences to the bereaved family on sad demise of Begum Kulsoom Nawaz".
The news was confirmed by PML-N president Shehbaz Sharif.
"The family has made a decision to bury Kulsoom Nawaz in Pakistan".
"She was a courageous lady", Siddiq-ul-Farouq, a stalwart party loyalist, told AFP, describing her as well-educated and dignified.
In a statement, he said all facilities will be provided to the family and heirs of Kulsoom Nawaz as per law.
"Feeling so sorry for Maryam and Mian sahib (Nawaz Sharif)", tweeted one user, Mobeen Shafaat.
Kulsoom was arrested by the military and immediately shifted to her local residence.
They were to remain in confinement for a year until Nawaz Sharif, having been sentenced to life imprisonment by a military court, was exiled to Saudi Arabia with his family after he agreed not to return to the country to practise politics for the next 10 years.
For her undergraduate studies, Begum Kulsoom Nawaz attended the Forman Christian College and then pursued a Masters degree at the Punjab University.
When Nawaz Sharif was deposed after his disqualification as a result of a Supreme Court verdict in July, 2017, Kulsoom Nawaz contested by-election from her husband's vacated constituency NA-120 and won the election.
But some observers pointed out that Kulsoom Nawaz was no political novice.
Up until her husband's ouster a year ago, Kulsoom Sharif had never been a politician, but she memorably led protests after the 1999 military coup that ended a previous Sharif administration.
Kulsoom was not able to take oath as a parliamentarian owing to her illness.