Two decades down, forever to go!
In the process, they also shared never-before-seen images from inside their marriage.
"Happy Anniversary ❤️ 20 YEARS," Isla captioned a tribute. "If there ever comes a day when we can't be together keep me in your heart. I'll stay there forever, Winnie the Pooh."
Sacha also posted the series of images and added his special touch of humor, writing, "Happy Anniversary my love. I'm writing this rather than getting you a card. Our duration is largely due to our location – after all Hollywood is the bastion of lengthy marriages."
The couple, who now share three kids, famously met at a party in Sydney in 2001 and later wed in Paris in 2010.
While the couple maintains privacy, they also speak about the support they get from one another. While talking to reporters at the Golden Globes after winning awards for "Borat: Subsequent Movie Film," Sacha said, "It's impossible to make a movie like this without having an incredibly supporting spouse."
"You know, I went and made two movies in the last 12 months: [The Trial of the] Chicago Seven and Borat 2," he continued. "And these aren't normal shoot days; you're calling up sometimes at the end of the day and just saying, 'I was lucky to make it out in one piece today,' so you need a very, very understanding wife. And I'm very lucky to have it."