Minnie Driver has urged people worried about the plight of marine wildlife to get involved with campaigning and making changes.
Minnie Driver says swimming with whales was a "religious experience".
The 'Good Will Hunting' actress - who gave birth to son Henry last September - loved getting the chance to swim with the sea creatures for a documentary in 2006.
She said: "Having my son and swimming with humpback whales were the two most religious experiences in my life."
The 39-year-old star - who is the new face of Dawn's Everyday Wildlife Champions campaign - is encouraging others worried about the plight of marine wildlife to join a new Facebook page dedicated to connecting similar individuals, and says she loves that her celebrity status helps her to urge people to get involved with campaigning.
She added: "We just have to remember that we're at the top of the food chain. And as Spider-man says, 'With power comes great responsibility.' I don't know why I quoted Spider-Man there, but it seems quite appropriate. We've got to do stuff or our kids are not going to have animals left or any oceans that we can swim in.
"I was raised to believe that we are custodians of this planet. This opportunity came up to be a part of something that brought something as everyday as Dawn washing-up liquid together with this Marine Mammal Center that I have worked with and that I love and support wildly. It just seemed like a great marriage.
"Celebrity is such a weird thing. It can really shine a light on stuff, which is the great aspect of it."