The mixed-use, leisure-led scheme includes a 10-screen cinema, up to 20 restaurants and a new public plaza.
The city centre development received detailed planning consent earlier in the year and is supported by the government’s regional growth fund.
WestQuay Watermark will be built alongside the WestQuay Shopping Centre that Hammerson co-owns, bolstering Southampton city centre as a place to visit.
The new development will be built in two phases. Initial enabling works on the site for phase one have begun and Sir Robert McAlpine’s main start on site is scheduled for the beginning of January. WestQuay Watermark is scheduled to open in autumn 2016. The second phase has the potential to include a hotel and a residential tower block with flexibility for retail and office space.
Hammerson development manager Guy Wells said: “Sir Robert McAlpine is a welcome addition to the WestQuay Watermark team. Their extensive experience of delivering high-quality schemes will be fundamental to the timely delivery and quality of the development.”