Rihanna has joked that she will "sneak into the polls" and vote with her son's passport, as she encouraged Americans to vote in the upcoming presidential election.

The Grammy-winning singer, who was born in Barbados and has not changed her citizenship, shares two-year-old son Rza and 15-month-old son Riot Rose with US rapper Asap Rocky.

Rihanna shared a video of herself looking out of a car window on Instagram, captioning it: "Me trying to sneak into the polls with my son's passport."

The 36-year-old used the hashtag #votecauseicant.

The Fenty Beauty founder is the latest celebrity to weigh in on the upcoming election, with a host of famous faces throwing their weight behind Democratic presidential nominee Kamala Harris.

Rolling Stones frontman Sir Mick Jagger said his children would be voting for Ms Harris, in an Instagram post shared before polling day on Tuesday.

Alongside photos of him with six of his eight children, the 81-year-old wrote: "Don't forget to vote - Jagger kids are voting for Kamala."

One photo showed Sir Mick joined by his four daughters - Karis, Jade, Elizabeth and Georgia May - while another saw him with two of his sons James and Lucas.

The Rolling Stones have previously criticised Republican presidential nominee Donald Trump for using their songs You Can't Always Get What You Want and Start Me Up during his rallies.

Meanwhile, Ms Harris has harnessed star power as she focused on battleground states in her bid for the White House with Beyonce, Eminem, Bruce Springsteen and Jennifer Lopez among those to have appeared at her campaign events.

Pop superstars including Taylor Swift and Madonna are also among those to throw their support behind her.

In the final weekend ahead of election day, Ms Harris stopped into Saturday Night Live in New York City to give herself a pep talk.

The presidential hopeful appeared as the "mirror image" of herself alongside actress Maya Rudolph, who reprised her role impersonating the vice president, during the show's cold open.