One Tree Hill stars Austin Nichols and Sophia Bush have visited the Gulf coast to examine the impact of the BP oil spill.
Bush, who has played Brooke Davis on the show since 2003, denied that their visit was an excuse for self-promotion.
"This isn't about celebrities putting their face on the cause," she told Zap2It. "We need to get together as people, because the numbers matter. We all have to write our congress. We all have to write our Senate. We all have to petition our president.
"The more of us that get involved in this and the longer that we clamour and scream and stand up for our rights, the faster the change will happen."
Her co-star Nichols (Julian Baker) added: "We went to an island that's a bird sanctuary, and there are barrier booms around it that are completely ineffective. You can see the oil just spilling over it. [They] do nothing.
"All of this is a reminder of the price we pay for being dependent on dirty energy. "
Bush concluded that she was "enraged and shocked" by the effects of the disaster.