Inside Leonardo DiCaprio's Star-Studded Charity Auction with Kate Winslet, Madonna and More

The Titanic costars reunited at the event — and auctioned off an extra-special prize. One lucky bidder was given the chance to have dinner with the longtime friends sometime in October or November at a place of their choosing in New York City.

DiCaprio spoke on stage at the annual event, hosted on July 26 in St. Tropez, France.

This year’s auction included works from renowned artists like Rashid Johnson, Sanya Kantarovsky, Adrian Genie, Damien Hirst, Jonas Wood and even Paul McCarthy. Proceeds from the gala and auction will support the Leonardo DiCaprio Foundation's environmental causes.

While $30 million has been raised so far, the auction continues online. Following last night’s preview, bidding will begin on August 10 and end on August 23.

Madonna performed as a surprise guest.

She later posted a video of her performance to Instagram, captioning the post, “Such an honor to be here supporting Leo’s foundation and doing what we can to save Planet Earth!”

It's no surprise the Spider-Man star showed up to support DiCaprio — the two have been friends for over 30 years.

Along with Penn, the star-studded gathering included Prince Albert II of Monaco, Penn's ex Madonna, Uma Thurman, Jared Leto, Cate Blanchett, Marion Cotillard, Kate Hudson, Edward Norton and Tom Hanks.

Titanic’s love triangle is back together again! The former costars posed for a photo together inside the event.

“Gangs back together. Now we’re saving icebergs. Go figure,” wrote Zane on Instagram, referencing LDF’s environmental protection work.

The occasion also happens to mark the film’s twentieth anniversary.

Winslet also helped auction off some Titanic memorabilia — including a signed life jacket from the film.

Following her performance, DiCaprio and Madonna posed for a photo together.

Kravitz also performed, taking the stage later in the evening with Madonna and DiCaprio dancing and singing along behind him.