A 33-year-old Robbie Williams fan stands to win £10,000 if she can convince her idol to marry her, bookmakers said.
Frances Ingram, from Chester, has placed a £10 bet at odds of 1,000/1 that she will wed the superstar.
And if her dream of marriage fails, Ms Ingram is willing to accept a single date with the star - which could net her £4,000 after she wagered a further £40 at 100/1 that the superstar would ask her out.
The store supervisor claims to be the singer's greatest fan and has his initials tattooed on her back.
Rupert Adams, a spokesman for William Hill, which took the bets, said: "It is one of the more original bets we have ever taken and it is the sort of wager that could become self-fulfilling.
"Everyone loves seeing the bookies taken to the cleaners and I am sure Robbie is no different.
"If he hears about the bet, surely he will ask her out."