The move represents further internal change at M&S, which earlier this month lost clothing and home boss Jill McDonald; marking another setback in its bid to turn around ailing clothing, home and beauty sales.
Dubinsky's departure is likely to come as a further blow to the business. A longtime member of staff, he's been with M&S since 2013 when he took on the top marketing role for the store's home department. In 2016, he was promoted to head of marketing, Christmas, a new role the store created to help it nail its festive strategy.
Most recently, he took on the remit of head of international marketing - a position he has held for over two years. During this time, he led M&S's first campaign specifically for the India market, which aimed to appeal to Indian consumers' fashionable side.
Between 2017 and 2018, M&S seen revenues fall by 2.9% for the group as a whole to $10.4bn. In the same year, over the 57 international markets it operates in (which include Europe, the Middle East and Asia) sales have declined from £1.1bn to £1bn.
Prior to joining M&S, Dubinsky was global brand development for Unilever's Dove brand.
It's understood the innovation position Dubinsky is filling at KFC is the one left vacant by Jack Hinchliffe, who was promoted to marketing director in April 2019.
He has been tasked with leading on new product development, concept innovation and customer experience for KFC, in the UK and Ireland.
The Drum has reached out to M&S and KFC for comment on his departure. At the time of writing, neither had responded.
It's not yet clear whether M&S will rehire for Dubinsky's position.
Dubinsky has stuck with the retailer through a significant period in its marketing history. Over the past 12 months, M&S's marketing team has undergone a significant change, ditching the top-down structure previously led ex-group chief marketing officer Patrick Bousquet-Chavanne, in favour of separate functions.
The marketing of its separate clothing and home, and food divisions are now overseen by Nathan Ansell and Sharry Cramond respectively, who report into divisional managing directors.
When McDonald departed from the clothing chief role in early July, M&S, group chief executive Steve Rowe assumed her responsibilities admitting the business needed "to move on at pace" to address longstanding issues in its clothing and home supply chain around availability and flow of product.