Singer Taylor Swift has urged her millions of fans to get behind the U.S. women's soccer team in its fight for equal pay, saying the world champions took a "historic stand" for equality.

The American singer-songwriter said that discrimination on pay is "happening everywhere" as she accepted the inaugural Teen Choice Icon Award on Sunday.

Alex Morgan, co-captain of the U.S. women's team, presented Swift, 29, with the award.

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"While they were winning the World Cup, they were also taking a historic stand in terms of gender equality, gender pay gap," Swift said.

"Please, please, please support [Morgan] and her teammates, because this isn't over yet. It's not resolved. Get online and talk about it."

The squad's 2-0 victory in the World Cup final in July capped a campaign that attracted vast television audiences.

In March, the team sued the U.S. Soccer Federation, arguing that their pay and working conditions amounted to gender discrimination.

The players, including Megan Rapinoe, Carli Lloyd and Morgan, said they had been consistently paid less than their male counterparts despite performing better.

The prize money for the women's World Cup doubled to $30 million this year, but this paled in comparison to the 400 million euros ($448 million) available for the men's tournament winners last year.

"Let people know how you feel about it, because what happened to them is unfair. It's happening everywhere, and they are heroes and icons for standing up," Swift said.

Last week, the U.S. Soccer Federation hired the services of two lobbying firms to counter the U.S. women's claims, a USSF spokesperson confirmed to ESPN FC.

In the wake of the U.S. women's team's World Cup victory, legislation was introduced in both the U.S. Senate and the U.S. House of Representatives requiring the USSF to pay players on the respective U.S. women's and men's national team equally.

The House bill, put forward by Rep. Doris Matsui (D-Calif.), would withhold federal funding for the 2026 World Cup, set to be hosted by the U.S., Canada and Mexico, if U.S. Soccer fails to pay the women's and men's teams equally. Sen. Joe Manchin (D-W.Va.) introduced an identical bill in the Senate last month.

USSF spokesperson Neil Buethe told ESPN FC that the hiring of the firms was not intended to combat the legislation being put forward, but rather an effort to ensure that the information available is accurate.

He added that the USSF received two separate letters asking for information, and that the hiring of the lobbying firms -- FBB Federal Relations and Van Ness Feldman -- was the best way to get that information across.

Buethe said in a prepared statement: "Due to the large number of requests we've received from policymakers since the Women's World Cup, we are taking the proper steps to make sure that those leaders have accurate information and factual numbers that will inform them about the unmatched support and investment the U.S. Soccer Federation has provided as a leader in women's football across the world."

Molly Levinson, a spokesperson for the players in the equal-pay lawsuit, said via text message: "We are stunned and disappointed that U.S. Soccer Federation -- the governing body for soccer in this country and a nonprofit organization -- would spend sponsor dollars and revenue to advocate against laws that ensure that women are paid equally to men.

"We can't imagine that fans or sponsors would support USSF's effort to misinform and mislead lawmakers about the facts by blatantly inflating numbers and minimizing and diminishing the work women players do.

"USSF should use their platform and resources to support equality in this country, not constantly fight against it."

Information from Reuters and ESPN FC U.S. correspondent Jeff Carlisle contributed to this report.