Gymshark, for its part, always signs talent exclusively to the brand. But that’s not all it’s about, brand marketing director Calum Watson assures. “We want people who actually want to be part of Gymshark. People who wear the product, know the community and believe in what we’re building,” he says. “That’s why Megan’s a multi-year partnership. We didn’t sign her for a campaign and a few Instagram posts. We want to build something together, long term.” It’s evocative of On’s approach with Zendaya, and Vuori’s with Kaia Gerber (and her trainer Kirsty Godso, who left Nike for the challenger brand after 13 years in 2025).

A post isn’t everything, but a post from the talent themselves can generate serious buzz. Bieber’s collection with Adanola, which went live on October 15, generated $7.3 million in media impact value (MIV) in one week, per Launchmetrics. Bieber herself drove 78% of the total value, and her own Instagram launch post was the top performing post, driving $794,000 in MIV.

Beyond the mega

The loyalty question isn’t just about the talent themselves, but the consumers. Big names may be visibility boosters, but if it’s loyalty brands are hoping to cultivate, they aren’t necessarily the best investment, experts flag.

“Those levels of engagement don’t necessarily translate into repeat purchases because consumers are often drawn to the lifestyle of a celebrity,” says Nia Pejsak, advisory director at Stylus. “The problem isn’t necessarily influencers moving between brands — it’s whether consumers stay interested in the brand once the celebrity moves on.”

The brands that do best are those that employ a mix of influencer tiers, says Laura Rocha Pulido, head of insights at influencer marketing and analytics platform Lefty. “While mega-influencer partnerships deliver instant awareness and cultural buzz, brands balance this by tapping mid-tier and micro-creators to drive community engagement and day-to-day volume,” she says. In the US at this stage, mega-influencers dominate impressions. Mega-influencers (1 million+ followers) account for 30% of total impressions on average, per Lefty. While they represent the largest tier, the remaining 70% is distributed across macro (26%), micro (23%), and mid-tier talents (21%).