Democrats are gathering in Philadelphia for the Democratic National Convention, which kicks off on Monday. The four day-long affair will see appearances by several political "rock stars," but will lack the high drama that characterized the Republican National Convention, says one expert.

Renan Levine, a professor of political science at the University of Toronto, says that unlike the Republican meeting, which wrapped up last week in Cleveland, the DNC will likely run according to plan.

"In many ways, it's going to be very different (than the RNC). Because it's going to be a much more, shall we say, 'smooth-running scripted affair,'" he said.

"The bad news is, if you're looking for high political drama, this one is likely to be boring."

One notable difference will be the number of high-profile Democrats attending the convention, showing their support for presidential candidate Hillary Rodham Clinton and her vice-presidential pick, Sen. Tim Kaine, Levine said.

"There's not going to be any talk of what Democrats are not going to be there … there's not going to be any talk of who's not endorsing the ticket," he said.

Last week in Cleveland, Sen. Ted Cruz refused to endorse Republican presidential candidate Donald Trump, urging voters to instead "vote your conscience."

To a chorus of loud boos and jeers, Cruz encouraged the audience to "vote for candidates up and down the ticket who you trust to defend our freedom and to be faithful to the Constitution." He was later excoriated by senior Republicans for his speech.

Levine said viewers can expect U.S. President Barack Obama, First Lady Michelle Obama, and former president Bill Clinton to all make appearances in Philadelphia in an effort to build support around Clinton.

"They're going to try and pull in Democrats, so Democrats who are not yet enthusiastic about Hillary Clinton will become enthusiastic about (her)," he said. "That's the whole main point of this, essentially, public relations exercise."

Protesters are planning rallies and demonstrations to coincide with the convention, which closes on Thursday.

Supporters of Bernie Sanders, the Vermont senator and former Clinton rival, are planning a protest for Sunday afternoon.

On Saturday, nearly 20,000 emails were leaked online , showing the hostility Democratic Party officials had for Sanders before he bowed out of the race.

With files from The Associated Press