"Giving clothes a second chance to go on the dance floor is a gorgeous way to help our planet," Van Ness wrote on Instagram. "Especially those lil bb walruses."
The colorful but classic tees and sweatshirts come from J. Crew, Victoria's Secret, Michael Kors and more major labels. Each unique top is emblazoned with phrases like "I Wear Used Clothes" and "Used Goods." (Van Ness chose a pink cropped hoodie.)
Also on board with the release are Lena Dunham and Sophia Bush, both of whom also showed off their new tops. Dunham snagged a white tee while Bush opted for a gray sweatshirt.
A portion of proceeds benefit thredUP's sustainable fashion initiative, which means this is one online purchase you can actually feel good about -- and just in time for Earth Day.
NEW YORK, NY - OCTOBER 02: Actress Olivia Wilde helps bring the slogan 'America Runs On Dunkin' to life at the Home That Runs On Dunkin, powered by recycled coffee grounds, on October 2, 2018 in New York City. (Photo by Cindy Ord/Getty Images for Dunkin' Donuts)
PACIFIC PALISADES, CA - OCTOBER 06: (EDITORS NOTE: Retransmission with alternate crop.) Olivia Wilde attends the Ninth-Annual Veuve Clicquot Polo Classic Los Angeles at Will Rogers State Historic Park on October 6, 2018 in Pacific Palisades, California. (Photo by Charley Gallay/Getty Images for Veuve Clicquot)
PARIS, FRANCE - SEPTEMBER 30: Olivia Wilde is seen arriving at Valentino fashion show during Paris Fashion Week Womenswear Spring/Summer 2019 on September 30, 2018 in Paris, France. (Photo by Jacopo Raule/Getty Images)
JIMMY KIMMEL LIVE! - 'Jimmy Kimmel Live!' airs every weeknight at 11:35 p.m. EDT and features a diverse lineup of guests that include celebrities, athletes, musical acts, comedians and human interest subjects, along with comedy bits and a house band. The guests for Friday, September 21 included Olivia Wilde ('Life Itself'), Noah Centineo ('To All the Boys I've Loved Before' and 'Sierra Burgess Is a Loser'), and musical guest Jungle. (Randy Holmes via Getty Images)
RICHMOND, CA - SEPTEMBER 17: Olivia Wilde attends the world premiere of the Audi e-tron electric SUV held at the Craneway Pavilion on September 17, 2018 in Richmond, California. (Photo by Kelly Sullivan/Getty Images for Audi)
HOLLYWOOD, CA - SEPTEMBER 13: Olivia Wilde attends the premiere of Amazon Studios' 'Life Itself' at ArcLight Cinerama Dome on September 13, 2018 in Hollywood, California. (Photo by Rich Fury/Getty Images)
HOLLYWOOD, CA - SEPTEMBER 13: Actors Jason Sudeikis and Olivia Wilde attend the premiere of Amazon Studios' 'Life Itself' at ArcLight Cinerama Dome on September 13, 2018 in Hollywood, California. (Photo by Jean Baptiste Lacroix/Getty Images)
TORONTO, ON - SEPTEMBER 08: Olivia Wilde attends The Hollywood Foreign Press Association and InStyle party during 2018 Toronto International Film Festival held at Four Seasons Hotel on September 8, 2018 in Toronto, Canada. (Photo by Michael Tran/FilmMagic)
TORONTO, ON - SEPTEMBER 08: Actress Olivia Wilde attends the 'Life Itself' premiere during the 2018 Toronto International Film Festival at Roy Thomson Hall on September 8, 2018 in Toronto, Canada. (Photo by Juanito Aguil/WireImage)
Actress Olivia Wilde joins a discussion about how the Sustainable Development Goals have been integrated into the content of Thomas & Friends childrens television series, in New York, on September 7, 2018. Thomas & Friends have teamed up with the United Nations to teach families about the Sustainable Development Goals today at the UN Headquarters in New York City. (Photo by Luiz Rampelotto/NurPhoto via Getty Images)
LOS ANGELES, CA - JUNE 20: Olivia Wilde attends the opening night of the 'Humans' at the Ahmanson Theatre on June 20, 2018 in Los Angeles, California. (Photo by JB Lacroix/WireImage)
HOLLYWOOD, CA - APRIL 18: Olivia Wilde attends the premiere of Netflix's 'Kodachrome' at ArcLight Cinemas on April 18, 2018 in Hollywood, California. (Photo by JB Lacroix/WireImage)
Olivia Wilde speaks at March for Our Lives in Los Angeles, California on March 24, 2018. The march was organized in response to the massacre at Marjory Stoneman Douglas High School in Florida where 17 people were killed in a mass shooting. Similar gun control rallies took place across the US. (Photo by Ronen Tivony/NurPhoto via Getty Images)
AUSTIN, TX - MARCH 10: Actress & producer Olivia Wilde walks the red carpet at the SXSW Film premiere of 'A Vigilante' on March 10, 2018 in Austin, Texas. (Photo by Jim Bennett/WireImage)
BEVERLY HILLS, CA - MARCH 04: Actors Olivia Wilde (L) and Jason Sudeikis attend the 2018 Vanity Fair Oscar Party hosted by Radhika Jones at Wallis Annenberg Center for the Performing Arts on March 4, 2018 in Beverly Hills, California. (Photo by Axelle/Bauer-Griffin/FilmMagic)
BEVERLY HILLS, CA - MARCH 02: Olivia Wilde attends the 11th Annual Celebration Of The 2018 Female Oscar Nominees Presented By Women In Film at Crustacean on March 2, 2018 in Beverly Hills, California. (Photo by Jon Kopaloff/FilmMagic)
LOS ANGELES, CA - JANUARY 28: Olivia Wilde at Steven Tyler and Live Nation presents Inaugural Janie's Fund Gala & GRAMMY Viewing Party at Red Studios on January 28, 2018 in Los Angeles, California. (Photo by JB Lacroix/WireImage)
LOS ANGELES, CA - JANUARY 20: Actor Olivia Wilde speaks onstage at 2018 Women's March Los Angeles at Pershing Square on January 20, 2018 in Los Angeles, California. (Photo by Amanda Edwards/Getty Images for The Women's March Los Angeles)
NEW YORK, NY - NOVEMBER 08: Olivia Wilde is seen on November 08, 2017 in New York City. (Photo by MediaPunch/Bauer-Griffin/GC Images)