The stars flew in for day seven of the event to celebrate the first showing of Florian Zeller’s drama, which received a 10-minute standing ovation.
British actress Kirby walked the red carpet in a delicate gold gown by Valentino haute couture, which she paired with a bold red lip, while Dern opted for a navy embellished gown and jacket by Armani Prive.
Jackman kept things classic in a black tuxedo.
Scroll through the gallery above to see more fashion from day seven of Venice Film Festival
Other stars who attended the premiere were Brazilian model Sara Sampaio, who wore a black sequinned long-sleeved gown. Italian reality television star Alessandro Basciano used the premiere as the opportunity to propose to his partner, Sophie Codegoni, who said yes in front of cheering crowds.
The premiere of biographical drama Dreamin’ Wild, starring Casey Affleck, Walton Goggins, Zooey Deschanel, Noah Jupe and Jack Dylan Grazer, also took place on Wednesday.
Affleck attended alongside his partner, actress Caylee Cowan, who wore a black lace gown, while Deschanel was clad in a pale blue satin one-shoulder gown from Dolce & Gabbana.
Elsewhere in Venice, the black-tie amfAR dinner took place, raising money for Aids relief. Singer Ellie Goulding was among those in attendance, wearing a metallic floral slip dress by Alberta Ferretti. Actress Marisa Tomei also attended, in a black dress with silver embellished panelling.
Venice International Film Festival kicked off on August 31 and is running until Saturday. High-profile premieres so far have included Don’t Worry Darling, starring Harry Styles, Florence Pugh, Olivia Wilde and Chris Pine, and Bones and All, with Timothee Chalamet, Taylor Russell and Michael Stuhlbarg.
On Thursday, the highly-anticipated Marilyn Monroe biopic Blonde, starring Ana de Armas, will have its premiere at the festival.