Sky News has learnt that Moonpig's owners are likely to announce in the next fortnight that the company will pursue an initial public offering (IPO) in London.
The unveiling of its intention to float will come just days after Paperchase, its struggling high street peer, filed a notice of intention to appoint administrators after its stores were forced to close during the latest English lockdown.
Moonpig, which has been owned by Exponent Private Equity since 2016, appointed investment banks last autumn to help it evaluate options for the business.
Citi and JP Morgan are leading the listing, which will value the company at more than £1bn and potentially as much as £1.5bn.
By floating as soon as this month, it will be the first in a queue of British "unicorns" to go public this year, with Darktrace, Deliveroo and TransferWise among those likely to list later in 2021.
Moonpig, which has built its brand in the UK through a spate of television advertising campaigns, sells online greeting cards and gifts.
It has captured market share from high street rivals such as Clintons and Paperchase, and has seen sales and profits soar during the coronavirus crisis.
During the first two months of the UK-wide lockdown, the company claimed to have added one million customers, and was the UK's leading shopping app during the summer period.
It also trades in the Netherlands under the Greetz brand.
A flotation of Moonpig would entail a return to the stock market for Kate Swann, the former WHSmith and SSP Group chief executive who is one of Britain's most respected corporate bosses.
Moonpig declined to comment.