The photogenic 24-year-old Dane is using a day off in the run up to Wimbledon to promote her newest commercial partner, Belgian chocolatier Godiva, and specifically the launch of their tennis-themed Sweet Caroline chocolate.

In front of selected guests in London she tries her hand at some intricate design work, but despite expert hand-eye co-ordination on court she is finding this an altogether trickier task.

"I love having input into the chocolates and spending a day with the team working it all out," she says cheerily, before taking time to pose for pictures and chat with the awe-struck guests.

That unaffected air explains her popularity with tennis fans (she has 1.35 million Facebook likes and 870,000 twitter followers), and also makes her a marketing man's dream.

Indeed Godiva says it believes this partnership will be a fruitful one, not only because of her playing skills, but also her "appeal well beyond the tennis court".
'Good fit'

According to Forbes Wozniacki made close to $11m (£6.9m) in 2014, with endorsements making up 85% of that total. Meanwhile, her total career earnings from prize money alone stands at $20m, with $600, 000 won so far this year.

The former world number one has major deals with global brands like Adidas, Babolat, Rolex, Sony Ericsson, Lavazza, and others including Dubai Duty Free, US vitamin firm Usana and Danish company E-Boks.

Her Adidas deal is reputed to be one of the most lucrative in sport, and she wears tennis kit specially designed for the German firm by Stella McCartney. She says that she only works with companies that she feels comfortable with, rather than concentrating just on the financial bottom line.

"I think carefully about what sort of deals I do. I like to be an ambassador for brands that I believe in, and that are a good fit for me as a person. That is why I am happy with this latest association - it is fun for me," she says.

"I am a tennis player first, and all of this - the commercial partnerships, would not be possible without the work on court. Things like this, it is my day off. My partners are very good about giving me the time I need for my tennis, and working around that."