Adam Lambert, Britney Spears, Ellen DeGeneres and Adam Rippon were among the celebrities supporting Thursday's Spirit Day.

Spirit Day supports efforts to combat the bullying of LGBT teens. Supporters were encouraged to wear purple on Thursday. Since its inception in 2010, GLAAD has played a prominent role in promoting Spirit Day.

At a Spirit Day fundraiser organized by songwriter Justin Tranter, Nick Jonas and Imagine Dragons frontman Dan Reynolds each donated $50,000 to GLAAD. Actor Darren Criss (Glee) pledged $5,000, according to Variety.

Britney Spears was GLAAD's surprise guest at its Spirit Day rally in Las Vegas held outside the T-Mobile Arena.

Out singer Adam Lambert helped raise money for GLAAD on social media.

“In honor of #SpiritDay, I'm raising money for @GLAAD!!” he tweeted. “Join me in taking a stand against LGBTQ bullying and supporting inclusion [purple heart emoji] Don't forget to go purple today too!!”

“Rocking purple today for #SpiritDay,” out figure skater Adam Rippon tweeted. “When we stand up for one another we are our best.”

Daytime talk show host Ellen DeGeneres messaged: “It's #SpiritDay. Let me see your purple.”

Other celebrities who offered their support included Sara Ramirez, Mariah Carey, Sia, Barbra Streisand, Ava Du Vernay, Eric McCormack, Sterling K. Brown, and the cast and crew of Queer Eye.

Numerous companies, television shows and sports teams touted the campaign's “stand against bullying” message, including the Los Angeles Dodgers, Washington Nationals, Chicago Cubs, New York Yankees, CNBC, NBA, Kellogg's, Times Square, Wells Fargo, Thomson Reuters, Target, Hilton Hotels, The Talk, Good Morning America, Instinct, Grey's Anatomy, and The Elvis Duran Show.

California Senators Kamala Harris and Dianne Feinstein were among the politicians who joined Thursday's campaign.