"Avengers" star Chris Pratt posted an Instagram photo of himself holding a plastic water bottle on Tuesday, prompting the ire of none other than "Aquaman" himself.

"bro i love u but wtf on the water bottle. no single use plastic. come on," commented actor and environmental activist Jason Momoa.

Pratt's post was a sponsored ad promoting his new partnership with Amazon. In it, he is wearing workout gear and leaning against a treadmill, holding the disposable water bottle in one hand.

"You’re probably wondering why I’m standing here, low key flexing, gazing into the distance... well, turns out I'm teaming up with @amazon to show you guys everything I use for my workouts, keeping active, and all that fun stuff to get you prepped for 2020," he wrote.

But news of the Amazon partnership was quickly eclipsed by Momoa's comment, which had nearly 50,000 likes and more than 1,000 responses as of Wednesday morning. Some said Momoa was being too harsh, while many others thanked him for calling Pratt out for holding an item that is one of the worst contributors to the world's ocean pollution crisis. Among those who thanked him: Pratt.

"Aquaman! You're completely right. Dammit," Pratt responded, explaining that he always carries around a "big gallon size reusable water jug," but that on that day, "If I remember correctly somebody threw that plastic bottle to me in the photo shoot cause I didn't know what to do with my hands!"

"My bad," he continued. "I don't want your home of Atlantis covered in plastic. Hear that kids? Reduce. Reuse. Recycle."

Amazon did not immediately respond to a request for comment from NBC News on Wednesday.

Momoa, who also played Khal Drogo in "Game of Thrones," has been an outspoken advocate of fighting climate change. In September, the Hawaii-born actor addressed the United Nations General Assembly, describing the impact that plastic in the ocean and rising sea levels have on island nations around the world.

"Island nations contribute the least to this disaster, but are made to suffer the weight of its consequences," he said. "Our governments and corporate entities have known for decades that immediate change is needed. Yet change still has not come."

In April, he shaved his beard as part of a video promoting recyclable canned water.

"Let’s make the switch to infinitely recyclable aluminum," he wrote in an Instagram post at the time.

Despite his commitment to his cause, he appeared to feel a little guilty for bringing attention to Pratt's plastic water bottle.

"I’m sorry this was received so badly today I didn’t mean for that to happen," he wrote in an Instagram post overnight of him along with a picture of Pratt with Momoa and his children. "I’m just very passionate about this single use plastic epidemic. the plastic water bottles have to stop i hope u make a reusable water bottle for amazon so we all can purchase."