The CEO of British supermarket chain Sainsbury's has apologised after being caught on camera singing 'We're in the Money" following the takeover of Asda.

Mike Coupe was preparing for an ITV interview to discuss the £7.3 billion ($10.1 billion) deal when caught on microphone singing a song from the musical '42nd Street.'

Coupe sang "we're in the money, the sky is sunny, let's lend it, spend it, send it rolling along." He later described it as "an unguarded moment" before settling down to speak.

He says it was "an unfortunate choice of song from the musical ... I saw last year and I apologise if I have offended anyone."

The value of Coupe's 1.28 million shares in Sainsbury's rose over £500,000 ($750,000) Monday after the deal's announcement.

The Sainsbury's and Asda merger is seen as a 'game changer' for the UK grocery market.

The deal combines Britain's second- and third-largest supermarket chains, giving the combined company 31.4 percent of the market and putting it ahead of the current leader, Tesco, which has 27.6 percent, according to data from Kantar Worldpanel.

The company will retain both the Sainsbury's and Asda brands - representing nearly £1 in every £3 spent on groceries - and there are no plans to close any of its more than 2,800 stores, the companies said Monday. They aim to lower retail prices as much as 10 percent as a result of the deal.

"This is a transformational opportunity to create a new force in UK retail," Sainsbury's CEO Mike Coupe said.

The move underscores the intense competition in Britain's grocery market as discounters take market share from traditional chains such as Sainsbury's and Tesco. Asda, Walmart's UK unit, has a strong presence in the north of England and Sainsbury's in the south.

Richard Lim, the chief executive of research group Retail Economics, described the deal as a "game changer" in the industry.

"The potential tie-up could deliver price reductions across a range of products, putting it in a position to challenge Tesco and the discounters head-on," he said in a statement. "Serving customers 'whenever and wherever they want' would take a giant leap forward with expertise in digital technology dovetailing with an expansive store estate."