Hillary Clinton's rally Saturday in New York got some extra exposure thanks to tweets from a handful of pop stars and other celebrities asking followers to watch a livestream of the event on Clinton's Web site.

In the speech, Clinton said that despite new faces among the Republican field, "they're all singing the same old song ... a song called 'Yesterday'" -- a reference to the Beatles' 1966 U.K. No. 1 hit. But also from yesterday are some of the divas who tweeted their support for Clinton.

In Clinton's defense, this particular mix of pop stars spans the generational spectrum, and they are savvy picks for targeting a wide swath of voters. But when you're campaigning on being the future, you've got to be selective with how many pop stars who haven't had a No. 1 hit since before you were first lady.

Here are the pop stars who tweeted about Clinton, and how long it's been since they've gone No. 1:

Katy Perry

Last No. 1 hit: "Dark Horse" feat. Juicy J
When did it go No. 1: 2013
What demographic does she reach: Millennials either still in school or paying off student loans but can afford to go to a Katy Perry concert and maybe buy an overpriced shirt while they're there. Less likelihood they will actually vote, but will post a lot about their political beliefs on social media regardless.

Mariah Carey

Last No. 1 hit: "Touch My Body"
When did it go No. 1: 2008
What demographic does she reach: Generation Xers who bought tickets to see Mariah Carey in Las Vegas and just want to go out and have some fun with their friends for the weekend because they deserve a break, you know?

Paula Abdul

Last No. 1 hit: "The Promise of a New Day"
When did it go No. 1: 1991
What demographic does she reach: Gen Xers who listened to Paula back in the day but mostly just spin Celine Dion, Adele and Josh Groban now. Already ready for the election to be over.

Barbra Streisand

Last No. 1 hit: "Woman In Love"
When did it go No. 1: 1980
What demographic does she reach: Baby Boomers who were disappointed Clinton lost to Obama in the 2008 primary and listen to both Babs and Katy Perry because their kids listen to her.

Perhaps not surprisingly, the by-far-most-retweeted call out came from today's bona fide current pop star, Katy Perry.