A couple from Slough spent a week unaware they had become multi-millionaires after forgetting to check their National Lottery ticket.
Donna Stickley was on a shopping trip when she remembered she had a ticket in her bag from the week before.
Husband David said his wife called him "all in a tizz" and had told her to check again as "things like this don't happen to people like us".
The couple won £21,044,592 in the Lotto Rollover jackpot on 12 May.
Originally, office manager Mrs Stickley, 48, thought they had won substantially less after misreading the jackpot prize money on the internet.
'Double check again'
Aircraft refueller Mr Stickley, 58, said: "My other half called me at work and all I could hear was lots of funny breathing down the phone, like something was wrong - she was all in a tizz.
"She said 'I've checked on the internet and I think we may have won £2m but it just doesn't look right'.
"I told her to go and double check again as things like this don't happen to people like us.
"She sent me a text with the amount on it from the internet but she had read the amount wrong - it wasn't £2m, it was £21m."
The couple intend to keep working for the time being and will go on a beach holiday and are considering buying a new car.
The winning ticket, with numbers 1, 15, 21, 30, 35 and 44, was bought from Casco Supermarket in Slough.