Robert Downey Jr. Reveals Truth Behind 'Avengers: Endgame' Line 'I Love You 3,000'

Iron Man himself came up with the viral "Avengers" phrase.

When it comes to Marvel movies, there’s one line in particular that fans “love 3,000.”

Early on in “Avengers: Endgame,” after Tony Stark (Robert Downey Jr.) figures out time travel, he puts his daughter Morgan (Lexi Rabe) to bed (because a parent’s work is never done). As he’s about to leave, he tells her, “Love you tons,” and she fires back, “I love you 3,000.”

Tony later repeats the line in a prerecorded final message following his death, making it 3,000% more emotional and sealing it as perhaps the most oft-quoted, oft-memed phrase from the movie. 

On Monday, around a year after the release of “Endgame,” directors Joe and Anthony Russo, as well as writers Christopher Markus and Stephen McFeely, joined ComicBook.com’s #QuarantineWatchParty to view the film remotely with fans. At one point, Downey Jr. popped in on Instagram Live.

The writers have already revealed that “I love you 3,000” came from Downey Jr. himself, and on Monday he explained.

“It was something that I think Exton, my now-8-year-old, used to say to me, and a lot of kids say, you know? It’s before they can quantify love they just think of the biggest number they know, and it’s usually like 2,000 or 3,000, whatever, and it turned out to be really significant,” said Downey. “But all the stuff in this movie was about us really starting to bring our own experience, lo these many years into these characters and the and the epic sojourn.”

Joe Russo added that having “emotional ownership” over what you’re working on pushes creators to do better work because of a connection to it.

“Probably, yeah,” Downey said. “And look, after 20-plus movies, we, the audience, our cast and crew, the whole planet was kind of in this resonance with each other and it was all leading up to this finale. So I mean I remember it so fondly. We were definitely, definitely, definitely, as you were saying, looking to stick the landing, and this was just one of those days that felt like just another day in the shoot, but we know when there’s important days you’re like, ’OK, this one kind of has to work or Act 3 isn’t as meaningful.’”

Throughout the #QuarantineWatchParty screening of “Endgame,” the Russo brothers shared behind-the-scenes info and videos, including Old Man Captain America, Chris Evans, looking a little more spritely than you’d think ... 

... and footage of Downey Jr.’s last day, fittingly adding, “We love this man 3,000.”