Warning: This post contains spoilers for Shang-Chi.

Mark Ruffalo slyly refers to the post-credits scene for Shang-Chi and the Legend of the Ten Rings while congratulating the cast and crew on their record-breaking opening. This past weekend brought about the debut of the latest MCU movie, Destin Daniel Cretton's Shang-Chi. As the franchise's first Asian-led movie and its first to open exclusively in theaters since the coronavirus pandemic began, there was a lot of interest in how it would perform. Shang-Chi scored the second-biggest three-day weekend of the pandemic and became the biggest Labor Day opening of all time.

Shang-Chi's financial success comes on top of critical acclaim as well, with the movie receiving some of the MCU's best reviews. The character of Shang-Chi, played by Simu Liu, is poised to play a big role in the franchise going forward, something that was teased in the movie's first post-credits scene. In it, Shang-Chi meets with Wong (Benedict Wong), Captain Marvel (Brie Larson), and Bruce Banner (Ruffalo) to discuss the mysterious Ten Rings and his future as a hero in a world that often needs them. In other words, it was setting up Shang-Chi's next MCU appearance.

Related: How & Why Shang-Chi Reverses Bruce Banner's Smart Hulk Transformation

Naturally, Ruffalo had to keep his involvement in Shang-Chi a secret ahead of its release. However, now that audiences are coming out in droves to see it, he couldn't resist letting a little tease slip on social media. On Tuesday, Ruffalo innocently asked, "Anyone catch that mid-credits scene in #ShangChi?" Knowing better than to say anything else, he added a sweet message for the Shang-Chi team: "Congrats to the cast and crew for the biggest Labor Day box office opening."

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Ruffalo has an unfortunate reputation for letting Marvel spoilers fly, with his biggest slip being when he accidentally live-streamed parts of the Thor: Ragnarok premiere. Since then, though, he's gotten much better with them, and recently he even skillfully evaded talk that the Hulk will appear in Moon Knight. His Shang-Chi post-credits appearance was surprising, and it's a testament to Marvel's own secret-keeping that it was a twist for so many fans.

Post-credit spoilers aside, it's nice to see Ruffalo being so supportive in regards to Shang-Chi's opening. Liu has already been welcomed by several MCU heroes, from Chris Hemsworth to Tom Hiddleston. He and the rest of the Shang-Chi cast are now a part of the Marvel family, and they already feel like they belong. With the post-credits scenes confirming characters like Shang-Chi, Xialing (Meng'er Zhang), and Katy (Awkwafina) will all be back, this is just the start of their journey. Having established MCU characters like Ruffalo's Hulk formally welcome them is fitting, so it's nice to see the same happen in real life as well.

More: Shang-Chi End-Credits Scenes Set Up 6 MCU Movies & Shows

Source: Mark Ruffalo/Twitter