On Monday, the singer-songwriter Taylor Swift endorsed two Democrats for the US mid-term elections, prompting Mr Trump to tell reporters that he likes "Taylor's music about 25% less now".
Swift's comments appear to have contributed to a spike in online voter registrations, especially among young people, according to the voter registration site Vote.org.
However, Vote.org said it was not possible to measure the direct impact of Swift's decision to wade into politics - taking into account looming registration deadlines in a number of states and other factors.
Swift's remarks once again puts her at odds with West, with whom she has had an on-off public feud since he interrupted her acceptance speech at the 2009 MTV Music Video Awards.
In September, West, who is married to Kim Kardashian, wore a hat with Donald Trump's slogan "Make America Great Again" during his performance of Ghost Town on the US comedy show Saturday Night Live.
He ended his segment by delivering an impromptu off-air speech praising the president, posted online by members of the audience.
"So many times I talk to a white person and [they] say: 'How could you like Trump, he's racist?'" he said. "Well, if I was concerned about racism I would've moved out of America a long time ago."
Rep. Maxine Waters, D-Calif., is facing scrutiny from a conservative watchdog group for possibly violating fundraising rules in a slate mailer, with the group requesting that Waters’ campaign committee be audited as a result.

The Federal Election Commission received a complaint Monday from the National Legal and Policy Center claiming that Waters, her campaign, and a pro-charter school group called Families and Teachers for Antonio Villaraigosa violated federal election law. The complaint claims the group paid $25,000 for Villaraigosa to be featured in the Waters mailer when he was running for governor in the Democratic primary earlier this year.

Although candidates can pay a fee to be included in slate mailers, it’s illegal for outside groups such as Families and Teachers for Antonio Villaraigosa to make such a payment.