Tribute act Mark Wright will headline the event at 2pm, before West Sussex County Council leader Louise Goldsmith, opens the area at 2.15pm.
The £1.2million project, which saw the repaving of Montague Place, installation of covered seating and removal of the concrete rotunda in favour of a new bandstand, was completed last month.
The project was a joint initiative between West Sussex County Council, Adur and Worthing councils, Worthing Town Centre Initiative and Coast-to-Capital Local Enterprise Partnership.
Jackson Civil Engineering was the contractor, with C2HM Hill acting as design consultants. A county council spokesman said: “The opening ceremony represents an opportunity for all of the partner organisations to recognise the individual and collective efforts in ensuring that the busiest street in Worthing remains a competitive and attractive destination for both residents and visitors.”
Mr Wright will continue performing between 2.30pm and 3pm. The event is the first since the area was revamped. S Club will lead Christmas celebrations in December, supported by Murdoch’s Crazy Eyes and other local acts.