Mark Ruffalo

Leonardo DiCaprio teamed up with Christie's to co-host the 11th Hour Auction in NYC last night. It was a successful event for Leo since the auction reportedly raised $35 million to benefit environmental and wildlife conservation efforts, almost doubling the goal of $18 million. He had the support of his long-time friend and Great Gatsbyco-star Tobey Maguire, who put in a winning bid on one of 33 pieces of contemporary art. Leo contributed something from his own art collection, a print called "Ocean V" by well-known photographer Andreas Gursky. Also out for the evening were Bradley Cooper, Mark Ruffalo and Salma Hayek.

It was Leonardo's second art-inspired outing in as many days, since he also made an appearance at the Brant Foundation Art Study Center's Andy Warhol showing in Greenwich, Connecticut, on Sunday. He'll be switching gears from art to film in the coming days, though, when he debuts The Great Gatsby in Cannes later this week.

Gwyneth Paltrow joined her Thanks For Sharing co-stars Mark Ruffalo, Tim Robbins, Josh Gad, and Patrick Fugit on the red carpet at the Toronto International Film Festival today. She accented her black dress with red animal-print heels to pose for the cameras. Gwyneth made the trip up north after popping up in LA for the annual Stand Up to Cancer telethon yesterday. She not only attended the event but was also an executive producer. Gwyneth talked about how losing her father to cancer changed her habits and made her take another look at her own health — see all the other stars that participated in Stand Up to Cancer's big fund-raising night here!

Keira Knightley and Jude Law stepped out for the world premiere of Anna Karenina at London's Leichester Square today. Keira got glamorous in a white Chanel Couture gown while Jude posed in a grey suit. Keira popped up overseas after spending much of the Northern Hemisphere Summer in NYC with her fiancé, James Righton. When she wasn't busy strolling the city streets with James, Keira filmed Can a Song Save Your Life? with costars Mark Ruffalo and Adam Levine. Keira's already lined up yet another project — she'll star opposite Chris Pine in the upcoming Jack Ryan. The movie may take Keira back to the Big Apple since production recently started there for Chris.

Chris Hemsworth, Tom Hiddleston, Scarlett Johansson and Mark Ruffalo were at Rome's De Russie Hotel on Saturday for a stop on The Avengers press tour before the guys headed to Germany, sans Scarlett, for yet another photo call yesterday. The foursome travelled abroad to promote the superhero movie all last week, kicking things off with an appearance in Moscow before moving onto London and then Italy together. The Marvel movie is expected to enjoy a big debut at the box office. Early reviews for The Avengers have been overwhelmingly positive and the movie is estimated to earn as much as The Dark Knight and The Hunger Games each did in their opening weekends. That could easily make The Avengers the biggest first-weekend earner among superhero movies to date. It opens in Australia on April 25.

The world premiere of The Avengers was held in LA today and lots of the movie’s big names turned out for the red carpet. Leading lady Scarlett Johansson stole the show in her black Versace dress, but her co-stars suited up handsomely as well. Chris Hemsworth slicked back his long blonde hair and fooled around with his Mjölnir (Thor’s hammer) with some journalists. Robert Downey Jr. wore a purple suit and was accompanied by his wife, Susan, who recently gave birth to their first son together. The film’s villain, Tom Hiddleston, wore a grey suit to the event like Jeremy Renner, who plays archer Hawkeye — Jeremy told media that his character would beat The Hunger Games’ Katniss Everdeen in an archery-off! Also walking the red carpet were Mark Ruffalo, Chris Evans, Samuel L. Jackson and comic book icon Stan Lee.