A renovation project worth £3.5 million has been unveiled which aims to transform Worthing Museum and Art Gallery.
Adur and Worthing councils have released details about the project, which they said would create 50 new local jobs and protect 20 current jobs.
They added that a further 24 apprenticeships would be created through an education programme for 2000 new learners in local schools.
Under the proposals, the grade II listed building in Chapel Road would be opened to the public in its entirety.
Currently just half of the building is accessible, and only 5% of its collection of exhibits can be put on display.
There are also plans for a new courtyard cafe and garden entrance on Richmond Road, along with greater retail space.
The plans have been announced as part of efforts to double the number of visitors to the museum and gallery within the next three years.
Cllr Heather Mercer, executive member for customer services on Worthing Borough Council, said:
“I am completely knocked out by these proposals.
“They will transform the museum into a stunning space fit to be a jewel in the crown of our cultural offering.
“Our culture department has great plans to fill this new building with fantastic new displays and exhibitions not of course forgetting some of the most popular existing items.”
Under plans drawn up by architects Allies and Morrison, the two historic interiors of the museum and library would be brought together into one seamless gallery.
Windows and skylights that had previously been blocked would be opened to allow more light into the building.
One of the proposals featured could see the museum become a national centre for costume research.
There are plans for a new costume research library to log more than 30,000 items in the collection at the museum.
The councils said they were seeking grants from groups including the Heritage Lottery Fund and Arts Council England to fund the development.
They are also looking to enter strategic partnerships with private and public funders, and have launched a public fundraising drive.
Worthing Borough Council is to pledge a further £125,000 towards the project.
Amanda O’Reilly, head of culture for Adur and Worthing councils, said:
“We are particularly excited by the proposal for a centre of excellence for costume trading on our fantastic collection, the breadth and depth of which is sadly not currently appreciated.
“We will be able to work with today’s designers, fashion students, makers, TV researchers, and costume historians to add real value to the museum and make it a nationally significant cultural destination. “