Actor-singer David Hasselhoff and syndicated columnist Dear Abby have joined the NOH8 Campaign, which raises awareness and funds for gay rights causes, including ending California's 2008 voter-approved gay marriage ban, Proposition 8.

The 59-year-old Hasselhoff is best known for playing Michael Knight in the NBC series Knight Rider and Los Angeles County lifeguard Mitch Buchanon in the syndicated series Baywatch.

Last year, Hasselhoff's daughter, 18-year-old actress Hayley Hasselhoff, posed topless for the NOH8 Campaign.

The NOH8 Campaign, which is helmed by photographer-activist Adam Bouska and his partner Jeff Parshley, photographs celebrities and everyday folks with their mouths duct taped and the campaign's familiar “NOH8” slogan often written on one cheek.

Hasselhoff is wearing a white t-shirt and gives two thumbs up in his photograph.

Dear Abby is photographed wearing a white business shirt as she crumples up a newspaper with both hands. Her advice column, simply called Dear Abby, is known for its “uncommon common sense and youthful perspective,” according to her publisher.

The campaign received a huge boost in January when NCIS star Pauley Perrette wore a strapless dress that featured the NOH8 Campaign's logo to the People's Choice Awards in Los Angeles.