Prince Harry and Ellie Goulding were reportedly seen kissing away from prying eyes during a polo match in Berkshire last month, sparking speculation that the pair are an item.
Rumours that Harry and Ellie are dating have seen bookmakers publishing odds on him popping the question to the singer.
Bookmaker Coral is offering odds of 5-1 that they confirm they are dating following a flurry of bets after The Sun newspaper's story about the couple.
Kensington Palace has declined to comment about the speculation.
Ellie is a friend of the younger members of the Royal Family, having sung at the Duke and Duchess of Cambridge's 2011 wedding reception. She also performed at the closing ceremony of Harry's first Invictus Games in 2014.
She sang at the polo match at Coworth Park in Berkshire where William and Harry played at the end of May, a few months after it was confirmed she had split from long-term boyfriend Dougie Poynter, bassist with the band McFly.
Coral's Nicola McGeady said: "Prince Harry has been linked with various women since splitting with Cressida Bonas two years ago but this latest rumour involving Ellie Goulding has sparked more interest than normal, suggesting that the pair are indeed an item."
The bookmaker has opened betting on things becoming more serious between the two, with odds of 50-1 that the Prince proposes to the star before the end of next year, and 100-1 that they wed.
Ellie has not responded to the story - instead posting a sultry selfie online.