'Dancing with the Stars' Premieres Tonight, Celebrities Prepare

"Dancing with the Stars" season 17 kicks off on Monday night with the celebrity cast prepared to sweep the ballroom despite many obstacles.

The season's new cast includes two contestants who are battling serious illnesses- actress Valerie Harper was diagnosed with incurable brain cancer in January, while TV personality Jack Osbourne has multiple sclerosis.

Not letting the cancer slow her down, Harper agreed when ABC and "Dancing with the Stars" came knocking at her door for the 17th season of the show earlier this year.

"When they asked, I thought, 'Why would I say no?' When life asks you to dance, you just have to dance," Harper recounted, according to People magazine.

Additionally, "it might prove inspiring to people to see a 74-year-old woman with terminal cancer dancing," she said.

Alternately, Osbourne hopes that the competition may inspire others suffering from MS.

"One thing I hope to accomplish is, I guess, mainly, just to kind of put it out there, in all seriousness, that when you get diagnosed with MS that your life doesn't stop and that you are still, for the most part, able to do [what] everyone else can," he said, according to ABC News.

Meanwhile, "Jersey Shore" star Snooki also joined the highly anticipated 17th season, followed by NFL star Keyshawn Johnson.

Moreover, "Pretty Little Liars" star Brant Daugherty will compete this year, followed by singer Christina Milian, Bill Nye "the Science Guy," and "Saved by the Bell" star Elizabeth Berkley.

"High School Musical" alum Corbin Bleu also stepped up to dance this season.

Rounding out the cast for season 17 was "Glee" star Amber Riley, comedian Bill Engvall, and finally, Leah Remini from the sitcom "King of Queens."

This season, the show will only air on Monday nights, eliminating the Results Show that usually followed on Tuesdays in past seasons. The Monday night episode will be two hours long.

Season 17 of "DWTS" will kick off on ABC on Sept. 16 at 8 p.m.

Viewers can vote for their favorite dance performance each week, and the votes will be combined with the judges' scores. Each week, the couple with the lowers score will be eliminated.