Stallone used Instagram to share that Schwarzenegger and his son Joseph Baena had dropped by Stallone's home for the holiday, with the Rocky star joking that the two brought the party.
Sharing a photo of the three men smiling together, Stallone wrote, "The big man and his son, Joseph , dropped by Christmas Eve And livened everything up!"
Schwarzenegger and Stallone have starred in multiple films together, including The Expendables franchise and 2013's Escape Plan.
Before that, however, the two weren't exactly friends, with Stallone revealing on the Tonight Show Starring Jimmy Fallon back in 2014 that he was not a fan of Schwarzenegger back in the '80s.
"We were very competitive," he said. "Yeah, I think hate's a good word."
"Did you ever hate somebody so much you go, 'I got to get to the gym?'" Stallone added, though he did have some kind words for his fellow actor.
"I really respect this guy, I think he's brilliant," he explained. "What he's done, what he's accomplished — he's had three different careers. But, I wanted to strangle him."
Now, Stallone and Schwarzenegger are clearly close pals, even spending time with one another's families, as evidenced by the Christmas Eve snap with Baena.
Baena is Schwarzenegger's son with Mildred Baena, his former housekeeper, and celebrated his 21st birthday in October. Baena has been taking after his dad when it comes to the fitness department, with Schwarzenegger praising his son's passion for weightlifting in a post for his birthday.
"Happy birthday Joseph! It's been fantastic to watch you pump up your muscles and your mind this year and I can't wait to see what's next," the actor wrote. "I'm proud of you and I love you!"
In addition to Baena, Schwarzenegger's son Patrick is following in his dad's footsteps in a different way by stepping into acting, though his dad noted that the 25-year-old isn't going for the action roles quite yet.
"Patrick, he works out every day, but he doesn't want to get too big because of the acting, because he's being sought after now for romantic roles, not action roles," Schwarzenegger explained to Men's Health. "But eventually, when he gets to be like 30, 35, he will go get bigger and then do more action movies. But I love seeing [my sons] work out and being into it. It's a great feeling."
Photo Credit: Getty / Todd Williamson