Chris Evans wished Robert Downey Jr. a happy birthday with a classic line from Avengers: Endgame. Downey Jr. is more than likely celebrating his 55th birthday indoors and practicing social distancing with a few family members. There will not be a huge party with dozens of people, though he could do so digitally through the use of social media. Regardless, the former Captain America actor is making sure Downey Jr.'s birthday does not go unnoticed.

Robert Downey Jr. started the Marvel Cinematic Universe with the first Iron Man movie in 2008. Chris Evans later followed in 2011's Captain America: The First Avenger and the two had instant chemistry together on the big screen when it came time for 2012's The Avengers. Now, Chris Evans is wishing Downey Jr. a very happy birthday. He posted an image of the two in character at Avengers HQ and captioned it with, "Happy birthday to one of my absolute favorites! Love you 3000," which is now a classic line from Avengers: Endgame.

"I love you 3000" is what Tony Stark tells his daughter early on in Avengers: Endgame. Stark has seemingly given up on the idea of returning to the superhero world after the events of Infinity War and Captain America: Civil War. So, he starts the movie out as a somewhat content family man out in the country. However, when Earth's Mightiest Heroes try to get the band together, Stark, begins to get pulled back into the world, despite denying it early on. Before we know it, he's looking for ways to work with the Pym Particles to get the time heist plan going.

From there, MCU finally see Steve Rogers and Tony Stark bury the hatchet after years of strife. It was the closure that many felt the characters needed and it was inevitable. In real-life, Chris Evans and Robert Downey Jr. also needed some closure with the superhero world. Both actor frontloaded fans by teasing that Infinity War and Avengers: Endgame could be the end of the line for their days within the MCU, which wasn't exactly what everybody wanted to hear. After years of training and intense shooting days, Evans and Downey Jr. were ready for a much-needed breather.

So, Avengers: Endgame gave Steve Rogers and Tony Stark proper send offs. Stark went from the billionaire, self-involved brat to the hero who makes the ultimate sacrifice to save the universe from Thanos. Rogers, who has always done what he thought was best for others, finally did what was best for himself as he went back in time to spend his remaining years with Peggy Carter. While Chris Evans and Robert Downey Jr. may not share scenes on the big screen again together, they, along with the rest of Earth's Mightiest Heroes, remain friends off the screen. You can check out Chris Evans' Twitter birthday message to Robert Downey Jr. below.