Andy Murray is not sure whether to bow or not but Serena Williams is taking no chances -- she is busy practicing her curtsy.
For Queen Elizabeth, whose favorite sport has always been horse racing, is coming to the world's most famous tennis tournament for the first time in 33 years.
She never misses Royal Ascot's annual festival of top-class racing. But she has not been to Wimbledon since her Silver Jubilee year in 1977 when Britain's Virginia Wade won the women's singles.
Current titleholder Serena Williams. who hopes to be playing in front of the Queen on Thursday if the draw works out, said "Wow, this is really, really cool."
"I've been working on my curtsy. It's a little extreme so I am going to have to tone it down," she said.
Murray is not quite sure what the etiquette will be.
"I don't want to be bowing and the person I'm playing with walks straight past or the other way round. You obviously need to have an agreement before you go on," he said.
Wade reckons the royal presence will help to energize the Scot and really fire up his game which has tapered off since he reached the Australian Grand Slam final in January.
Last year, when Murray became the first Briton in 71 years to land the pre-Wimbledon tournament at Queens, the monarch sent him a note of congratulations.
Britain, which invented the game of tennis and hosts its most glamorous tournament, has not enjoyed success at Wimbledon in the men's singles since the glory days of Fred Perry way back in the 1930s.
BBC commentator Max Robertson was beside himself with excitement after Wade's victory: "Virginia Wade has won the centenary title with the Queen watching her. Virginia will be taking tea with the Queen."
Organizers are hoping -- shocks permitting -- that Queen Elizabeth will get to watch both Murray and Williams when she takes her seat in the royal box on Thursday.
But if Murray fulfils the sporting dreams of a nation, she will not be able to return next week for the final -- she and Prince Philip will be on a state visit to Canada.
