Flashback: CNN contributor who warned of sexist coverage of Biden VP once mocked Ann Romney

A new group called “We Have Her Back” promises to make sure that the future running mate of presumptive Democratic nominee Joe Biden will receive fair coverage from the media, but one of the signatories vowing to defend the female VP pick from "sexist" attacks was once under fire herself for remarks she made about Ann Romney during the 2012 election.

CNN commentator Hilary Rosen was one of several prominent women who signed an open letter calling on media outlets to refrain from using misogynistic tropes against the soon-to-be-announced vice presidential candidate. Rosen, alongside former Obama senior adviser Valerie Jarrett and Planned Parenthood CEO Alexis McGill Johnson, urged journalists at all levels to be conscious about how they report on the running mate.

“We are reaching out now because we are about to embark on a historic moment – once again – having a woman on a presidential campaign ticket. While you have already done significant reporting on the process, we know you are actively preparing for coverage about the specific Democratic vice presidential nominee,” began the letter addressed to news division heads, editors in chiefs, bureau chiefs, political directors, editors, producers, reporters and anchors.

HILLARY CLINTON RIPS NY TIMES' MAUREEN DOWD FOR CLAIMING WOMAN HASN'T BEEN ON DEM TICKET IN '36 YEARS'

“Given how few women have reached this point, the sometimes disappointing coverage of the process to date and the double standards we’ve seen in the public and media expectations of women leaders over the years – and even more so for Black and Brown women leaders – we wanted to respectfully share some thoughts with you about the media’s role in the scrutiny and coverage of women and women of color candidates in general, and the vice-presidential candidate in particular,” the letter continued.

Rosen, however, was not always this concerned about how women are portrayed by the media.

In 2012, the CNN Democrat mocked Ann Romney, wife of then-GOP presidential candidate Mitt Romney, saying she "never worked a day in her life" despite how the potential first lady had raised five sons at home.

Facing heavy backlash, Rosen offered a mea culpa.

"I apologize to Ann Romney and anyone else who was offended," Rosen said at the time. "Let's declare peace in this phony war and go back to focus on the substance."

CLICK HERE FOR THE FOX NEWS APP

There has been growing speculation that Biden will be announcing his running mate ahead of next week's DNC convention. Those reportedly on his shortlist include Sen. Kamala Harris, D-Calif., former Obama national security adviser Susan Rice, Rep. Karen Bass, D-Calif., Gov. Gretchen Whitmer, D-Mich., Rep. Val Demmings, D-Fla., Atlanta Mayor Keisha Lance Bottoms, Sen. Tammy Duckworth, D-Ill., and Sen. Elizabeth Warren, D-Mass.

Fox News' Brian Flood contributed to this report.