With an exclusive field - eight singles players and eight doubles teams - the combinations enjoy a level of crowd support and luxury they don't usually experience.
"It's a huge highlight," said Venus, from his five-star hotel. "When Raven Klaasen and I first spoke about playing together, it was our goal to make it to London. So to be here, around all the other players, it's great.
"It's a big arena and usually completely full. There is one singles and one doubles each session, and people tend to come out for both. And the court is the only thing that is lit up, with the crowd in darkness. The atmosphere is unique and everything about it, the whole experience, is almost perfect really."
Venus, playing alongside American Ryan Harrison, reached the semifinals last year on his London debut. He would love a repeat and admits there are no excuses for peak performance.
"Our hotel looks out over the London Eye and our suite has a few rooms," said Venus. "A private boat takes us straight up to the pier each day. It's not your typical tournament transport. And the food ... there's no holding back on the food. Basically they have everything you could need or want, and if they don't, you could ask for it and they will get it."
World No 14 Venus and Klaasen (13) have enjoyed a strong season. The high points were the final at SW19, another decider at the Toronto Masters and a title in Marseille.
But they also reached the quarter-finals at five Masters 1000 events and made ATP finals in Japan and Holland.
"We have been very consistent," said Venus. "In the first five or six months, we were doing well, making quarters of some big events. Then we had a breakthrough at Wimbledon and that showed us, in those big moments, we can beat the good teams. I like where we are at."
Venus and Klaasen are the sixth seeds, pitted against second-seeded Colombians Juan Sebastian Cabal and Robert Farah, fourth seeds Jamie Murray of Britain and Bruno Soares (Brazil) and seventh-seeded Croatian Nikola Mektic and Austrian Alexander Peya in group play.
The rewards are lucrative, with a US$100,000 ($148,000) appearance fee per team, US$38,000 ($57,000) for each group win and much more for progress beyond that.
And during the week, Venus also gets to mix with Federer, Djokovic and the other legends of the sport.
"You definitely see more of each other, because there's less people here," said Venus. "Every time you see them, it's 'hi, how ya doing' and they are nice and friendly. Everyone knows everyone and it's definitely a special thing to be part of."