Arnold Schwarzenegger decided to poke some fun at his old buddy Sylvester Stallone on social media. Stallone has Rambo: Last Blood hitting theaters this evening and Schwarzenegger wanted to wish him luck at the box office. However, he couldn't resist having some fun with Stallone and made a joke about the knives they both signed for charity. The two action mega stars were once rivals back in the day, but they have since become great friends and co-stars who enjoy giving each other a hard time on social media.

In the video message to Sylvester Stallone, Arnold Schwarzenegger compares the knives they both gave to charity. Stallone's is signed and it looks like it was used in Rambo: Last Blood. However, Schwarzenegger brings out an even bigger knife, which was used in Predator and did the famous Crocodile Dundee dialogue about knives.

While Arnold Schwarzenegger's Australian accent needs some serious work, his humor is on point. He says, "Good luck with Rambo this weekend, Sylvester Stallone. I loved it, and when it's a hit I'm going to buy you a new knife to celebrate."

Related: Can Rambo or Downton Abbey Steal Pennywise's Box Office Crown This Weekend?

Sylvester Stallone was pretty happy about his old friend's message and even reposted it to his social media accounts. But, he did have something to say in response. Stallone said, "Thank you very much big man. You're a great friend, and a great star, but my knife is always going to be sharper than yours!" It's nice to see the two friends having fun on social media together to promote a charity and Rambo: Last Blood at the same time. Once the promotional tour is finished for the upcoming movie, there are many who are hoping that Arnold Schwarzenegger and Stallone will reunite on the big screen for Expendables 4.

Sylvester Stallone has teased Expendables 4 a few times this year. Back in March, he shared a picture of himself, Arnold Schwarzenegger, and Bruce Willis, which obviously had fans excited. Then, on the Fourth of July, the actor posted a picture of himself from the franchise and revealed he had some new inspiration to work on the story. While there isn't anything concrete, we should end up hearing about the highly anticipated sequel in the next few months and find out who will be starring alongside Stallone when the cameras start rolling.

Sylvester Stallone has his sights set on Rambo: Last Blood this weekend. The sequel is estimated to make anywhere from $20 million to $24 million. This could be enough to take down IT Chapter Two, which has held the number one spot for the past two weeks. However, there will be some other competition with Ad Astra and the Downton Abbey movie both debuting this weekend too. Regardless, it looks like Stallone should be able to take the win for the weekend, as long as the earnings end up on the higher end of the spectrum. While we wait to see how Rambo: Last Blood does in theaters, you can check out Arnold Schwarzenegger's Instagram message to Stallone below.

Kevin Burwick