Katharine McPhee shared a set of sizzling snaps on Instagram.
The pics, which were uploaded to her feed on April 20, saw the actress posing in her underwear.
The black set included a plunging bra and low-rise bottoms.
McPhee also sported a basic white t-shirt and briefs, which were wet and see-through in the pics.
McPhee posed on the shallow part of the sea at Malibu beach.
She wrote in the caption: “Happy (almost) Earth Day! 🌍 I love that each year, this day is meant to remind us that we should all try & do our part to take better care of the planet that generations to come will inhabit.”
She added: “I’ve teamed up with my family at @minddbra to launch our Oceana Collection.”
While also sharing that “10% of the sales of this collection will be donated directly to @Oceana – a non-profit near & dear to my heart, dedicated to preserving & restoring the world’s oceans.”
McPhee also noted that she’s “grateful” for “working with a female-founded bra company that is deeply committed to sustainability.”