Friday prayers are to be held at Istanbul's iconic Hagia Sophia building for the first time since the celebrated museum was turned back into a mosque.
"Muslims are excited, everyone wants to be at the opening," Istanbul Governor Ali Yerlikaya said on Thursday.
The 1,500-year-old Unesco World Heritage site became a museum in 1934.
But earlier this month, a Turkish court annulled Hagia Sophia's museum status, saying its use as anything other than a mosque was "not possible legally".
Turkey's President Recep Tayyip Erdogan then announced that the world-famous site would be used as a mosque for Friday prayers from 24 July.
The move was criticised by religious and political leaders worldwide.Hagia Sophia was built as an Orthodox Christian cathedral and first converted into a mosque after the Ottoman conquest nine centuries later.
What will prayers at the site look like?
In a televised address on Thursday, Governor Yerlikaya urged those attending prayers on Friday to bring "[face] masks, a prayer rug, patience and understanding" as measures to help prevent the spread of Covid-19 would be in place.
He added that healthcare workers would be made available at the site.
Turkey's religious affairs minister, Ali Erbas, said that about 1,000 people would be able to attend prayers at the site at any one time.
He said that "modifications" had been made inside and that a "garden setup" had been prepared, adding that the site would remain open overnight.
A turquoise carpet was laid on the floor to prepare for prayers and Christian relics were reportedly covered up with white drapes or obscured by lighting.
Scaffolding was erected inside the dome as builders scrambled to convert the interior of the ancient building.
Among the Christian mosaics expected to be obscured during Muslim prayer was the ninth-Century mosaic of the Virgin Mary and Jesus inside the apse.
Mr Erdogan is expected to be among the worshippers on Friday.
Why was Erdogan's move controversial?
Islamist groups and devout Muslims in Turkey had long called for the Hagia Sophia to become a mosque again, but secular opposition members opposed the move.
When President Erdogan announced the decision to do so on 10 July, it was met with widespread criticism.
Pope Francis responded by saying that his "thoughts go to Istanbul," adding: "I think of Santa Sophia and I am very pained."
The head of the Eastern Orthodox Church, Patriarch Bartholomew I, warned that the conversion of the building would "disappoint millions of Christians" and fracture two worlds.
The World Council of Churches, which counts 350 churches as members, called for the decision to be reversed, saying it would sow division.
Unesco said it deeply regretted the move, which further enflamed tensions with neighbouring Greece, home to millions of Orthodox followers.
But Mr Erdogan defended the move, stressing that the country had exercised its sovereign right.
"After 86 years, Hagia Sophia will serve as a mosque again, in the way Fatih the conqueror of Istanbul had indicated in his deed," he said.
He added that the building would remain open to all Muslims, non-Muslims and foreign visitors.
What's the history?
The iconic, domed building sits in Istanbul's Fatih district, on the west bank of the Bosporus, overlooking the Golden Horn harbour.
Hagia Sophia's complex history began almost 1,500 years ago, when Byzantine emperor Justinian built the huge church in the year 537.
In 1453, in a devastating blow to the Byzantines, Ottoman Sultan Mehmed II captured Istanbul (formerly known as Constantinople) and the Hagia Sophia - an Orthodox Christian cathedral - was converted into a mosque for Friday prayers.
Four minarets were added to the exterior, while ornate Christian icons and gold mosaics were covered with panels of Arabic religious calligraphy.
After centuries at the heart of the Muslim Ottoman empire, it was turned into a museum in 1934 in a drive to make Turkey more secular.
It has since become one of Turkey's most popular tourist sites, receiving more than 3.7 million visitors last year.