Watch Replay: Hillary Clinton and Michelle Obama at Winston-Salem, North Carolina Rally

Michelle Obama made her first campaign appearance with Democratic presidential nominee Hillary Clinton on Thursday in Winston-Salem, North Carolina, in what was meant to encourage early voting in the battleground state.

Clinton warned Thursday the "dignity and respect for women and girls is also on the ballot in this election," taking a clear shot at Republican presidential nominee Donald Trump and his treatment of women, before Michelle Obama spoke.

"Michelle reminds us to work hard, stay true to our values, be good to one another, and never, ever stop fighting for what we believe in," Clinton said. "She has spent eight years as our first lady advocating for girls around the world to go to school."

She added: "Seriously — is there anyone more inspiring than Michelle Obama?"

Michelle Obama has become Clinton's most powerful campaigner — a bit of a surprise given the grueling and sometimes bitter primary race in 2008 between Clinton and then-Senator Barack Obama.

Watch the replay of Michelle Obama and Hillary Clinton in Winston-Salem, North Carolina.

However, beginning with her July Democratic National Convention speech in Philadelphia, Michelle Obama has attempted to boost Clinton's favorability ratings by pitching the Democratic nominee as one who would be best suited for preserving President Obama's accomplishments and who would rise above the most negative elements of the presidential cycle.

“When they go low, we go high,” Obama said at the convention — a line that Clinton has since used against her Republican rival Donald Trump.

The importance of Michelle Obama's role in the election cycle isn't lost on the White House, including the president himself.

“I think the president would admit that his wife is an enormously influential and powerful surrogate in support of Secretary Clinton,” White House press secretary Josh Earnest told reporters at a daily briefing last week.

“Those things, I think combine to make her a very powerful advocate for Secretary Clinton and probably make her the most powerful advocate that Hillary Clinton has,” said Earnest, speaking of the first lady's rhetorical ability, as well as her willingness to make a personal appeal for Clinton.

The Hillary Clinton-Michelle Obama connection has apparently gotten under the skin of Trump.

“We have a bunch of babies running our country, folks. We have a bunch of losers. They’re losers,” Trump said at a campaign in North Carolina last week. “They’re babies. We have a president — all he wants to do is campaign. His wife, all she wants to do is campaign.”

A New York Times Upshot/Siena College survey released on Tuesday shows that Trump’s standing in North Carolina has crumbled, with Clinton holding a seven-point lead — 46 percent to 39 percent — among likely voters in a three-way race that included Libertarian nominee Gary Johnson.

In recent national polling, Clinton leads head-to-head match-ups against Trump, with the Democrat holding 48.6 percent support compared to 43.2 percent for the New York businessman, according to averages compiled by RealClear Politics.

Photo credit: Hillary Clinton via Gary Smith, Flickr; Michelle Obama via Tim Pierce, Flickr