Architect Edward Said is urging the authorities to save a door on Mrabat Street in St Julian's which is all that is left of a UCA house where actor Joseph Calleia once lived.
The 19th-century house has been demolished to make way for a guesthouse.
"What should have become a museum, a major attraction and monument to this Maltese legend, is now destroyed," Said wrote on social media.
The heritage conservation practitioner said that the house, called Jo-El, served as the residence of Calleia and his wife Eleanore when the star retired from filming in 1963.
Calleia is deemed one of Malta's most successful emigrants of the 20th century.
He started his career in musical comedy in the US, before making it to Broadway productions.
He rose to fame with his role as a villain in the play Small Miracle in 1934 and eventually made it to Hollywood starring in movies including Algiers, Five Came Back, Golden Boy, The Glass Key, Gilda, The Jungle Book, Touch of Evil and Zorro.
On Wednesday, Said admitted he was not an expert in filmography and was not pointing fingers at anyone linked to the development on Mrabat Street.
However, he decried the demolition of the house, saying it was the first in Malta to be fitted with an elevator, air-conditioning and intercom. This in itself, he said, gave the house architectural value.
Said affixed a photo of Calleia on the solitary door, with a note informing passersby that the man once lived there.
According to a permit granted in 2019 and which expires next year, the house is being demolished as part of a development that will see the construction of a guest house on five floors including a shop at ground level.
The applicant was Ivan Azzopardi and the architect was Jesmond Mugliett.
The Planning Authority's Case Officer had recommended the refusal of the development as it breached car parking standards as laid out in the Strategic Plan for Environment and Development.
The case officer had said the development would give rise to unacceptable additional on-street car parking. The area, they added, already suffered from a parking space shortage.
The Superintendence of Cultural Heritage had also opposed the development, urging for the retaining of the façade.
The site, it had said, consisted of two buildings within the Urban Conservation Area of St Julian's, and the preservation of the visual integrity of the streetscape was a priority.
It had warned that rock-cut tombs and Second World War public air-raid shelters had been recorded in the vicinity.
"While the internal demolition of the existing buildings is not being objected to, the demolition of the existing façade is not acceptable from a cultural heritage point of view.
"One of the buildings still retains its original cornice and parapet wall (opramorta), which are typical features which complete the façade. The proposal should be redesigned to retain and integrate the existing façades up to and including the existing cornice level where this is existing (which must not be damaged or interrupted) and the parapet wall."
Din l-Art Ħelwa had also objected to the demolition of the UCA dwellings.