Hau will continue to lead the Group M division's regional sports consulting practice while broadening his responsibilities across the wider regional content portfolio.
In Black's new role, he will continue to build the division's activation capabilities across the region and bring greater discipline to its business development.
Both Hau and Black will be based in Singapore.
Balasingam previously spent three years at Mindshare and also had stints at British American Tobacco as well as in outdoor media.
"Increasing demand for innovative branded entertainment solutions has seen our business grow significantly over the past 12 months. To ensure we remain at the forefront of this fast moving arena we are continuing to strengthen our team," said Mike Rich, ESP Asia-Pacific chief executive.
ESP, which stands for Entertainment, Sports and Partnerships, is GroupM's content creation division responsible for the development of integrated content solutions for brands across the entire Group M client list.