Clarkson previously endorsed Republican candidate Ron Paul last year, but Paul lost the party's nomination to former Massachusetts Governor Mitt Romney.
The 'Mr Know It All' singer has now explained that she opposes Romney's conservative social policies, according to the Daily Star.
"I've been reading online about the debates and I'm probably going to vote for Obama again, even though I'm a Republican at heart," Clarkson said.
She added: "I can't support Romney's policies as I have a lot of gay friends and I don't think it's fair they can't get married. I'm not a hardcore feminist but we can't be going back to the '50s."
Clarkson also mentioned that she likes the US president and his wife Michelle Obama personally, even if she doesn't agree with all of their policies.
"Obama is a great guy. I've met him and I'm a fan of Michelle too," she explained.
"[Michelle] has been busy promoting better education and healthy diets, which is something we could all use a dose of reality on."
Madonna, Katy Perry, Jay-Z and Beyoncé and Anna Wintour have all endorsed Obama in the past several months.
Romney counts Donald Trump, Kid Rock and Clint Eastwood among his celebrity supporters.
Watch the lyric video for Kelly Clarkson's 'Catch My Breath' below: