The Japanese star has made collaborating with fashion designers a feature of major tournaments and she caused a stir in the first round when she took to the court wearing a long black skirt and jacket, which she removed to reveal a sequinned gold dress.
For her second-round clash with Croatia's Donna Vekic, Osaka donned a golden bomber jacket and long ivory train.
"For the outfit, the inspo (inspiration) was, I don't want to say Victorian, but the ladies that have the dresses with the poof in the background," she explained after her 7-6 (1) 6-4 victory.
Osaka's use of the tennis court as akin to a runway has divided opinions, with her first-round opponent Laura Siegemund telling German TV: "I couldn't care less. I come here to play tennis, not to put on a fashion show."
But Vekic is a fan, saying: "I think it's good that she's doing different things, expressing herself through fashion. Whether it's good (fashion) or bad, that's a different thing, it's fashion.
"Some people take tennis way too seriously. Relax, it's just an outfit. It's not such a big deal. She has the opportunity to do that, so why not?"
While Osaka's tennis has been overshadowed by her clothes, this is her best run at Roland Garros since 2019 and she will take on American teenager Iva Jovic next.
The 16th seed, meanwhile, revealed that, like Coco Gauff, she has been involved in a minor car crash in Paris.
"I wasn't scared for my life, but I was just, like, 'Whoa, this bus is really backing up into us', and you could hear the car crunching," she said. "That was a really interesting situation. So I hope it doesn't happen again today."
Defending champion Gauff moved into the last 32 with straight-sets win. She saw off Mayar Sherif 6-3 6-2.
Sixth seed Amanda Anisimova only needed to spend 25 minutes on court, taking the first set 6-0 against Julia Grabher before the ailing Austrian called it a day.
Meanwhile 23-time grand slam champion Serena Williams is reportedly in discussions over a return to professional tennis at Queen's Club next month.
A podcast hosted by Andy Roddick, a good friend of Williams, reported on Thursday that the 44-year-old is set to play doubles in London.
Williams has not played a match since a glittering farewell at the US Open in 2022.