Now that Kelly Clarkson and boyfriend Brandon Blackstock have gone public with their relationship, they aren't hiding it. At all. Word is they engaged in a PDA sesh on the set of 'The Voice' -- even though Clarkson is no longer mentoring on that show since she has her own reality singing competition in the form of 'Duets.'

So why were Clarkson and her BF canoodling on another show's set?

Well, Blackstock manages 'The Voice' coach Blake Shelton.  So when Clarkson visited her old haunts to see her new boyfriend as he tended to his client, they engaged in lovey dovey behavior. We're happy that Clarkson is happy, even if she did turns heads with a smooch fest.

A source told Radar Online, “They kissed hello. It was pretty adorable and you can tell they’re passionate about one another. She just wanted to support her man and watch him in action. Plus, she’s become good friends with Blake, so she wanted to say hi to him as well. They seemed pretty buddy-buddy; they hang out a lot."

Even though Clarkson was walking wounded, having injured her foot recently, she still hobbled around on set. Where there's a will, there's a way! "She could have easily stayed home,” the source said. “She wanted to be there though and be by his side." Sounds like the 'Dark Side' singer is totally in love.

Blackstock is a good BF, it seems, at least according to the insider who witnessed their PDAs. “He was super cute, opening all her doors and making sure she was comfortable and felt at home on set,” the source admitted. “He was completely doting on her and she couldn’t have been happier. Their love is real.”

Too cute!

Watch the Kelly Clarkson 'Dark Side' Video