The new outfit will feature an existing client base that includes Bayer Schering, Ikea, Johnson & Johnson and Lufthansa.
Former journalist Watt will become unit MD, after serving as head of search engine optimisation, digital PR and social media at MindShare.
She told PRWeek the new venture would focus on blogger relations, community management and online reputation.
'Conversational media is now recognised as a key part in informing and delivering results across the digital and offline marketing mix,' said Watt.
Watt caused a storm in the PR world earlier this year when it was revealed media agency MindShare was pitching for and winning PR accounts (PRWeek, 9 May).
The new unit follows Profero's launch last year of The Hive, a social media planning division spanning the digital agency's global operations.
'When we announced the launch of The Hive last year, we were clear in our views - social media must not sit in a silo,' said Profero Europe chief executive Daniele Fiandaca. 'Having integrated social marketing across the agency, we simply recognised we needed to invest in additional talent.'