Denise Richards is mourning the death of her French bulldog, Hank; the actress revealed on Twitter Tuesday that her family pet has passed away, Us Weekly reports.

"Last night we lost our beloved Hank. I will miss him dearly, 13 year old . . . been there for me through it all," she tweeted.

Later, Richards expressed gratitude for the many messages of condolence she received from fans, tweeting, "Thank you so much for your kind messages about Hank . . . it means a lot to me. You guys are the best . . . so thoughtful and kind."

Richards has long been an animal advocate. The actress volunteered at the North Shore Animal League in November to care for animals rescued from Hurricane Sandy.

"During their visit Denise and her family fell in love with Tara the Labrador Mutt-i-gree puppy and welcomed her into their home!" North Shore said on their Facebook page with an accompanying photo of Richards with the black lab puppy. According to her Twitter page, she renamed the dog Lily.

Mother to three young daughters, Sam, 8, Lola, 7, and Eloise, 19 months, Richards told Omg! from Yahoo! that she enjoys getting her kids involved with animal welfare.

"I have a lot. I converted my garage into a dog bedroom," she told Omg! "And it's good for my girls. For my daughter's birthday party, in lieu of gifts, we asked if anyone was interested in donating blankets and dog food and cat litter and my daughter dropped it off at the shelter."

"So, it's nice for them to know and to learn to give back. And they're very nurturing, which is great for the animals."

In addition to joining their mother volunteering with North Shore, the girls also tag along when she works at animal shelters, according to the Daily Mail.

The Best Friends Animal Society is another the animal organization with which Richards is involved. She volunteers with their Pup My Ride program, rescuing shelter dogs that are scheduled for euthanasia.  

She revealed in a blog for iVillage last year that she has also adopted several special needs pets, including one that was starved and suffering from cancer, one with an amputated leg, one that came from a hoarding situation and one that was born with no eyes.

“These dogs were all going to be euthanized. They are so loving and so happy at our home,” she wrote.

“There are so many puppies at the shelters. I would strongly encourage you to adopt!”