Laura Hoyle, 39, and Kirk Stevens, 37, matched all six numbers to win £10,000 a month for the next 30 years in the Set For Life draw on March 1.
But the pair were unaware they had won the life-changing amount for almost two weeks – and even carried on playing the game believing they had won just £5.
It was only when Laura logged in to her Camelot account on March 13 that she realised they had landed the top jackpot prize.
The couple, who live in Hucknall, have already bought a Porsche Cayenne and plan to spend their winnings on pursuing their dream hobby of becoming home and furniture designers.
Laura said: “I did get an alert just after the draw saying there was ‘good news about my ticket’ but I assumed I had won a fiver.
"I had received the same message before so didn't think too much of it.
“I even kept on playing for several more Set For Life draws before I got an email from Camelot requesting I log into my account and check my messages.
"I thought that was odd and even asked Kirk whether he thought it was real or not.
"I finally checked the app and saw there were lots of notifications there.
"It was then that the penny finally dropped that we should call Camelot fast.”
Laura, who works for a logistics firm, said it was impossible to stay focused on work when she finally called up to check how much she had won.
She added: “I was working from home that afternoon and stopped immediately to call Camelot.
"I was physically shaking as I told the lady, ‘I think I’ve won the lottery.’
“It was so weird saying those words, I kept thinking this must be a joke it can’t be happening to us.
"And the ridiculous part was that, as I waited for Camelot to call me back, I still had to join work meetings online.
"I could hardly speak, let alone make any sense."
The celebrations started almost immediately, with Kirk popping open a bottle of Prosecco before Laura had even finished the call with Camelot.
Laura added: "By the end of Friday evening, we had finished off four bottles of Prosecco between us.
"Kirk fell fast asleep but I couldn’t sleep a wink, my mind was still racing and I stayed awake all night.
"The only thing I could do was to watch movies so I stayed up and watched the complete Divergent series, which helped pass six hours at least.
“We have always been busy people and we have lots of plans and ambitions.
"This win means we are literally set for life and we are so excited about the future.”
The pair also contacted their families to share the good news – but it took some persuasion to convince their nearest and dearest that it wasn’t a wind-up.
Kirk said: “We called our parents first to tell them the news.
"Laura’s mum really wasn’t sure and decided to wait until we had it confirmed by Camelot before offering her congratulations.
“My mum was even more sceptical – she put the phone down on me three times.
"She kept saying, ‘you are having me on,I don’t believe you’
"When I called her back a third time, she said ‘get Laura to call me’ and put the phone down again.”
Despite his huge win, Kirk says he has no plans to leave his job at Rolls Royce, and the couple are planning to use the money to pursue their hobbies and interests.
In Laura’s case, she hopes to develop her interest in home makeovers and design into a property management business.
And Kirk, who works as an aeronautical engineer, is passionate about carpentry and is now setting up his own workshop to create bespoke wood furniture in his spare time.
Kirk, who started his career in the Royal Navy as an aircraft mechanic, added: “I have no plans to leave my job at Rolls Royce. I love the work and have been there for 14 years.
"I am also currently studying a Master of Science degree in advanced manufacturing systems with Brunel University London and want to see that through.
"But it would be fun to design and build furniture at the weekend.
"It is something I have always wanted to try.”
The pair have no children but plan on spoiling their two beloved cocker spaniel dogs, Teddy and Barney, with the money.
Laura joked: "I told Kirk I needed a run-around for me and the dogs and before we knew it we were trying out a Porsche Cayenne.
“This win, with the help of my savings, has meant we could put down a deposit on the Porsche and use it straight away.
"It is amazing to drive and even the dogs seem rather pleased with their new surroundings.”
Laura and Kirk bought their £1.50 winning Set For Life Lucky Dip ticket online via the National Lottery app.
The winning Set For Life numbers for the draw on March 1 were 9, 14, 19, 35, 37 and the Life Ball was 6.