Arnold Schwarzenegger leads birthday tributes to Sly Stallone

Arnold Schwarzenegger has sent birthday wishes to Sylvester Stallone.

The former California governor shared a thoughtful Instagram post in honour of his friend's 78th birthday, featuring a few images of the pair throughout the years.

"Happy birthday my friend, @officialslystallone," Schwarzenegger captioned the post. "You are a champion and a legend. You inspire me and billions of people around the world."

The Terminator star included snaps of himself and Stallone carving pumpkins together, smiling at a Planet Hollywood event back in the day and posing in some very '80s outfits.

In April, Stallone and Schwarzenegger discussed their past rivalry with each other on TMZ Presents: Arnold & Sly: Rivals, Friends, Icons.

Schwarzenegger admitted that Stallone "was very helpful in my career because I had something that I could chase," while Stallone said that when Schwarzenegger came along "I was like, 'Finally, something to motivate me.'"

"As soon as I saw him, it was like bang, two alphas hitting," Stallone added.

Stallone also received birthday love from his family, including daughters Sistine, Scarlet and Sophia, as well as his wife, Jennifer Flavin.

Among the birthday shout-outs from his girls, Sistine shared some wholesome throwback snaps on her Instagram Stories, where she called the actor "the greatest dad".

"I feel so lucky to have you," she wrote.