The singer, who is part Native American, fears activists are too busy celebrating their victory in North Dakota, following a decision by the U.S. Army Corps of Engineers to re-route the controversial Dakota Access Pipeline, when they should be preparing for the next environmental struggle.

And now newly-elected U.S. leader Donald Trump has reopened the controversial Dakota Access Pipeline debate, taboo insists there's no time to sit back.

"We knew that there was still a big war against injustice," he tells TMZ. "We felt like we needed to do whatever we can, because some people were like, Yeah, we did it! Everybody can go home now!' but it's never over, especially when we're dealing with this man who has come into office. He's unpredictable. You've got to be on guard."

Taboo is a staunch supporter of the Standing Rock Indian Reservation's fight against the pipeline, and he was part of a weekend rally for Standing Rock at the Sundance Film Festival in Utah.

Actress and activist Shailene Woodley was also part of the rally.

On Tuesday (24Jan17), President Trump announced he had signed orders to move forward with the construction of the Keystone XL and Dakota Access pipelines.