Codenamed "Project Solar", Sainsbury's £7.3 billion deal with rival British supermarket chain Asda is an alignment of planets years in the making.
In order to keep it secret, Asda, owned by US giant Walmart, was dubbed "Mars" and Sainsbury's "Jupiter" by the teams working on the takeover, a source with direct knowledge of the talks said.
The coming together of the two was eventually sealed by a group of retailing executives who have been crossing orbits as both rivals and colleagues for decades.
Indeed, Sainsbury's chief executive Mike Coupe and Roger Burnley, the CEO of Asda, have a shared history that will aid with the integration of the two cultures, Walmart International chief Judith McKenna said on Monday.
Coupe, 57, will lead the combined business, while Burnley, 51, will continue to run Asda, which will keep its brand. The two are friends and Burnley became Asda's chief executive in January knowing that a deal with Coupe was on the cards.
"Mike and Roger's ability to work together from a previous life is really helpful," McKenna, an Asda veteran who worked with Coupe at the supermarket group in the 1990s, said.
Coupe, who grew up in West Sussex and enjoys playing the guitar and cycling, was a graduate trainee at consumer goods giant Unilever who then moved to Tesco's marketing department before joining Asda in 1993. He became its trading director before departing in 2001, following Walmart's £6.7 billion takeover of the British supermarket company in 1999.
After 18 months running frozen food business Iceland, Coupe went to Sainsbury's, becoming its trading director in 2004 and succeeding Justin King as its CEO 10 years later.
Meanwhile, Yorkshireman Burnley started as a graduate at DIY chain B&Q before joining Asda as its supply director in 1996, while Coupe was there, and then taking a key role in the Walmart integration.
In 2002 he was poached by Matalan to become the discount retailer's supply chain director, before reuniting with Coupe at Sainsbury's four years later.
Burnley spent a decade at Sainsbury's, rising to become its retail and operations director and working closely with Coupe, only to return to Asda as its chief operating officer in 2016.
Like Coupe, Burnley is a keen cyclist, and also enjoys sailing, snowboarding and running in his spare time.
However, despite the friendship between the pair, the tie-up between Britain's second- and third-largest food retailers stems from talks that Coupe held with David Cheesewright, McKenna's predecessor who retired as CEO of the US firm's overseas arm, Walmart International, in January.
"We've been talking to each other for a while," Coupe said. "It goes back to some conversations that Dave Cheesewright and I had quite a period of time ago, but things really got going this time last year."
That was after rival supermarket giant Tesco agreed a £4 billion takeover of wholesaler Booker in January 2017 in a bid to strengthen its grip on Britain's food retailing market.
If the acquisition of Asda is cleared by regulators, it is expected to result in Sainsbury's leapfrogging Tesco to become the UK's largest supermarket operator by market share. It is Coupe's second deal, following Sainsbury's 2016 purchase of Argos.
As long-time brokers to the company, advisers from UBS and Morgan Stanley worked with Sainsbury's on the Asda deal as well as the earlier Argos acquisition. Walmart is being advised by Rothschild and Credit Suisse.