Jessica Biel, Behati Prinsloo, Hunter McGrady and several others joined Upton's #ShareStrong campaign
Kate Upton Jessica Biel Whitney Cummings
Credit: Kate Upton/Instagram; Jessica Biel/Instagram; Whitney Cummings/Instagram

Kate Upton’s strength in the gym is obvious — she and her trainer frequently post videos about her latest weightlifting PRs — but it takes more than just muscle to hit her workout goals. It also takes motivation and mental strength, and the Sports Illustrated model is encouraging everyone to share what empowers them with her new campaign.

Called #ShareStrong, Upton, 27, said in an Instagram video that the aim of the campaign is for people to post photos and videos “talking about who or what inspires us to be our best selves.”

“It’s to spread positivity and inspiration by creating a community that talks about encouraging, empowering stories and self-motivation,” she added.

Upton said that her inspiration is her 9-month-old daughter Genevieve.

“She motivates me every single day to be the best mom I can be for her,” she said. “To be my strongest self, and to set a good example.”

Upton asked her followers to #ShareStrong on social media, and tons of celebrities chimed in, from Jessica Biel to Behati Prinsloo to Hunter McGrady.

“Spreading some self love today with zero filter and zero makeup for my girl @KateUpton,” Biel, 37, wrote. “She’s on a mission to encourage everyone to feel strong and love themselves *as they are*… and I’m so honored to help spread that message. Take a second to show the real you.”

RELATED VIDEO: Behati Prinsloo Shows Off Her Post-Baby Body in Bathing Suit 2 Weeks After Daughter Gio’s Birth

And Prinsloo, 31, got real about life as a mom.

“Here’s to the sleepless nights, bleeding nipples, crying, laughing, the highest of highs and lowest of lows and everything in between,” the mom to Dusty, 2, and Gio, 1, with husband Adam Levine wrote on Instagram. “I won’t change a single thing, being mom to Dusty and Gio keeps me strong, motivated and empowered. This is my #sharestrong thanks @kateupton for starting this.”

Several of Upton’s fellow SI Swimsuit model friends also joined in. McGrady said that meditation keeps her strong.

“It’s up to you to make healthy choices. Not just healthy choices for your body but healthy choices for your mind,” the 26-year-old newlywed said. “When our mind is right, everything else follows. In order for me to have a successful day, I have to meditate or take time out to pray. It’s so crucial to take care of yourself FIRST.”

And model Lily Aldridge talked about mom strength too.

@KateUpton asked me to share what & who makes me feel Strong and without hesitation being a Mother gives me strength in ways I didn’t know possible 🖤,” she said. “My children are my source of love & strength everyday!”

Actress and comedian Whitney Cummings had a message for the young adults growing up online.

“My #ShareStrong is for all the young women that follow me on social media,” she said on her Instagram Story. “I want them to know that it’s okay to make mistakes, it’s okay to ask for help and it’s okay to not take yourself seriously all the time.”

“And it’s also okay to stutter,” Cummings, 36, added, as she jokingly struggled to say “#ShareStrong.”