Florence Pugh has never been afraid of fashion controversy. Last July she set off a viral brouhaha when she appeared at the Valentino couture show in Rome in a sheer pink gown that showed her nipples, then posted on Instagram defending her choice and her body. She followed that with an appearance at the Venice Film Festival in September for the premier of “Don’t Worry Darling” in a sparkling Valentino gown-’n’-shorts that became known as her “revenge dress” after rumors surfaced about on-set spats with her co-star Harry Styles and the director Olivia Wilde. She followed that with another debate-sparking Valentino look at the Oscars.

Now, on May 1 she is making the Valentino relationship official and will attend her first Met Gala with Pierpaolo Piccioli, the creative director of Valentino, not just as his date, but as the star of the coming Rockstud bag campaign.

That makes them the latest “It” couple in the pop culture round-robin otherwise known as the celebrity-fashion dating game, an increasingly frenetic sport in which allegiances changes with dizzying speed.

Zendaya, last year’s face of the Valentino Pink PP campaign, is now at Louis Vuitton. Kim Kardashian, late of Balenciaga, is suddenly in Dolce & Gabbana ads. Such whiplash-inducing switches from one style to another can make it hard to believe that the transaction is anything other than a cynical bargain between fame and money (as opposed to, say, an expression of actual personal taste). Perhaps not unexpectedly, however, Ms. Pugh and Mr. Piccioli have some thoughts about shilling, style, and what it all means.

How did this begin? With a friendship, or a business deal?

Florence Pugh: We’ve had, like, a speed-dating relationship since just after the couture show where I wore that pink dress. I did have a lot of positive comments, but I was surprised that people felt they were allowed to be really awful and say some disgusting things because of me showing my nipples.

Even though the dress was daring, it wasn’t in any way gratuitous. It wasn’t over-sexualized. It was basically this beautiful dress and this beautiful fabric, showing off whatever it was that I had underneath. I just could not wrap my head around the fact that showing my breasts was causing such anger — to the point where people were saying that if I got hurt, I deserved it. That was why I had to comment.

Pierpaolo Piccioli: I wanted to talk to her after that. The statement was the perfect one to embody the idea I was talking about months ago about not having canons of beauty, but being unique and different and diverse and showing yourself in a fierce way. Florence was just asking for respect about a choice, which is exactly what I’m saying when I do my collection.

FP: So we had this FaceTime, and at the end we both said it feels like we’ve been mates for decades. Now we send each other pictures of each other on Instagram a lot. He’s become best friends with my dad. We’re completely in each other’s lives.

PP: Doing a campaign together means sharing values, not only an aesthetic. It’s about standing for the same things. Otherwise you feel it is fake — just wearing something and making your first pose.

FP: When we were shooting the campaign, I was wearing the apricot couture dress that I wore to my “Wonder” premiere, and Pierpaolo and I found the snack table. Obviously the snack table was absolutely amazing, but I’m in a dress that cannot be stained. So he’s basically helping me stuff food in my mouth. He’s also smoking. There’s tomato oil bread dripping everywhere. And lots of people looking at us, like, “Please do not ruin this day. Otherwise we’ll kill you.”

In a lot of campaigns, it seems as if celebrities are simply selling themselves to the highest bidder. Did you ever worry about that?

FP: I always felt like I’d be very nervous about a fashion or beauty campaign because what if it’s not me? So many times I’ve had to stand up about the way people talk about my body or the way people have tried to change my body. Here I was allowed to show a version of myself doing all of my faces, not sell a version of someone to help sell the products.

PP: In the campaign, Florence is screaming, laughing, crying — that’s why she’s there rather than just a model. You really get the difference. I think you have to feel the person in front of you, not the dream of a lifestyle. I think it’s completely over, that idea of a campaign.

FP: There have always been ties with people and businesses where you’re like … well, that doesn’t make any sense or that’s just happening because it’s the hot thing right now.

PP: We talk a lot about values in fashion — about inclusivity, different proportions of bodies, diversity. But sometimes you just feel it’s a trend. So I feel it’s important that you have a real relationship with someone, to show values through imagery. When we shot the campaign in New York. Florence’s father, mother and grandma joined us on the set.

FP: My grandmother had just flown from London, and she put her heels on to come and see the Valentino team. But then her feet hurt, so she decided, oh, I’m going to take my shoes off.

PP: The grandma wanted the paper slippers from the set. So I sketched on the slippers the studs on the bags and the shoes Florence was showing, so her grandmother could have something Rockstud too.

FP: When we were leaving. I was like, “Granny, we are never ever going to wear these again. We’re going to frame them.”

Is your Met dress going to surprise people?

FP: It’s big, but we like big, don’t we? When I’m on those red carpets, there is so much pressure because you’re either selling a movie or trying to make a moment. They’re nerve-racking. The whole point is that you are expressing yourself with what you are wearing. Every time I step out in whatever dress, that’s a version of me that I’m really proud of. So it doesn’t matter if people don’t necessarily like it. I don’t think anything that I do has to be 100 percent loved. Things being up for debate is good. It means people are interested.

PP: Drama is what the evening is about. You have to play with the steps.

FP: There’s so much glamour on the carpets, and people who know how to pose and walk, and you’re like, oh my god, I’m so out of my depth. But to have this person with you who designed the dress after talking and planning and creating for months takes away 30, 40 percent of the fear. The idea is to be as bold as possible. I love the power that it gives me. I love how it sparks conversation.

PP: For a designer, you don’t create objects only. You create objects that have to be worn by someone. And Florence is the person that makes sense of what I am doing.

So is this a long-term relationship?

FP: Would I jump ship? Yeah, no, I wouldn’t jump ship. It’d be like getting married and then being like, “Oh, OK — bye!!!” It wouldn’t make sense.