Now that’s a rock!

Liv Tyler officially confirmed her engagement on Instagram after ET announced the news in September. She also posted a sweet message to her fiancé, David Gardner.

PHOTOS: Liv Tyler Is Engaged -- See the Ring!

“Crazy about my man!!!!! sweet sweet daddy , friend , fiancé,” she captioned the image. “Thank you !!!!!! Grateful”

The adorable couple wore all black and matching smiles in the photo.

Although the pair is just announcing the big news now, ET learned the couple has been engaged since December but kept the news private.

Tyler and Gardner welcomed a boy, Sailor Gene, back in February. This is the second child for the Leftovers actress, 38, who shares a 10-year-old son, Milo, with her ex-husband, Royston Langdon. Gardner also has an 8-year-old son, Grey, from a previous relationship.

PHOTOS: Liv Tyler Shares the Cutest First Photos of Her New Baby Boy Sailor

The proud mother, who is rather private about her relationships, has shared many adorable snaps of her sons (and future step-son) on Instagram.

As we all wait for the wedding, check out these amazing celebrity engagement rings in the video below.