Five times a year, thousands of people throng the Istana during open house for a look at what lies behind its cast-iron gates.
Soon, people can get a view of its treasures all year round.
The Government is building a heritage gallery at Istana Park, opposite the Istana's main gate in Orchard Road, to display selected artefacts and state gifts from the President's official residence.
It will also have a gift shop.
The museum is expected to draw 120,000 visitors each year.
It comes amid ongoing efforts to rejuvenate the Civic District and educate a younger generation about its historic landmarks such as the former City Hall and Supreme Court, which reopened as the National Gallery last November.
The President's Office said of the Istana Heritage Gallery yesterday: "The project was initiated by the President. It is part of the overall efforts to educate the public on the history and heritage of the Istana, which is a national monument."
The main three-storey Istana building was completed in 1869 and was the official residence of colonial governors, before being renamed when Singapore became self-governing and again on independence.
It is now open to the public on five public holidays, and gets 14,000 visitors at each open house.
In recent years, President Tony Tan Keng Yam also launched guided tours of the grounds and building for visitors on these occasions.
Heritage experts welcomed the gallery project, saying it can be designed to engage people while explaining the historical significance of the Istana and the presidency.
Architectural historian Lai Chee Kien said it also presents an opportunity to chronicle the storied Orchard Road area.
Its notable landmarks include the pre-World War II Japanese Consulate-General bungalow atop Mount Emily, the House of Tan Yeok Nee at the corner of Penang Road and first Prime Minister Lee Kuan Yew's house in Oxley Road.
"There are so many gems, not just in architecture but also in our landscape history at the periphery of the Istana," he said. "This is an excellent opportunity to chronicle many different time periods in Singapore's history by connecting the Istana to its immediate neighbourhood."
The museum, the size of three four-room Housing Board flats, will stand on a space that has a water pump room and covered shelter. Renovations costing $900,000 are expected to be completed in the second half of the year.
The Istana is looking for an operator to run it for three years, sources said. It said in a letter to potential operators that they will not be charged a licence fee for three years. In return, the operator must have a social and public education element in running the museum. This includes "providing opportunities for volunteerism, or donating a percentage of the profits from the retail outlet to a charity".
The operator can choose to run the museum for another six years, but may be charged a fee for each three-year extension.
Experts stressed that the museum's contents and how they are organised and presented are key to its success.
Said Singapore Heritage Society executive committee member Yeo Kang Shua: "After 50 years of diplomatic ties with countries all over the world, there should be a sizeable collection of state gifts.The question is how you curate them to tell a compelling story."
Dr Kevin Tan, president of the International Council on Monuments and Sites Singapore, felt that outsourcing the museum's operations might compromise the dignity and prestige of the President's Office, and suggested it be run as a state- funded national education project.
Photographer Ahmad Iskandar, 29, said many Singaporeans will be keen to know the story behind the gifts leaders give one another.
"What will be really interesting is if the items marked important visits that helped shape our history," he said.