The star couldn’t possibly have looked more proud as he made his acceptance speech for the Best Actor gong, for his role in ‘The Revenant’.
Completely transfixed on Leo, his former ‘Titanic’ co-star welled up with tears.
Her reaction was shared all over the internet, with fans going wild for their adorable friendship.
The pair had earlier arrived on the red carpet together, 18 years on from when they played lovers Rose and Jack in ‘Titanic’.
OK BUT I WAS HOPING WE WILL GET KATE WINSLET BEING ALL EMOTIONAL AND STUFF DURING LEO'S SPEECH AND WE GOT IT pic.twitter.com/tDQbHdnl8n— laura (@daisyrdley) February 29, 2016
OMMMMMMGGGG MY KATE-LEO HEAART https://t.co/lvAnkNdZ5l— hana (@jaeeabd) February 29, 2016
During his acceptance speech, Leonardo called on the world to do more about climate change.
"Making ‘The Revenant’ was about man's connection to the natural world,” he said.
“We felt in 2015 it was the hottest year on the planet. Climate change is real, it's happening right now, it's the most urgent threat affecting our entire species, we need to work right now and stop procrastinating."
See all the red carpet pics from the Oscars in the gallery below...