The answer: It depends.

“Voters don’t want to think Hollywood celebrities are telling them how to vote. They understand their expertise is outside the political world,” said Darrell West of the Brookings Institution.

But there are exceptions. Oprah Winfrey is one. She helped launch the career of then-candidate Barack Obama in 2008, lending the largely unknown Illinois senator much-needed credibility in his race against Hillary Clinton.

Also, celebrities can give a boost with certain targeted audiences. …

“People who do read a publication like US Weekly probably aren’t on political websites,” said Jennifer Peros of US Weekly. “But when they see pictures of these celebrities in these magazines endorsing the presidential candidates, they definitely are paying attention more.”