Rock singer Melissa Etheridge is the latest celebrity helping raise money for the campaign to uphold Maryland’s same-sex marriage law.

Melissa Etheridge performs in Los Angeles in 2010. (AP Photo/Donald Traill)

In the e-mail solicitation, Etheridge, who is gay, cites her friendship with Maryland Del. Heather Mizeur (D-Montgomery) and her spouse, Deborah, for getting involved with Question 6 on Maryland’s ballot.

“I’m helping Marylanders for Marriage Equality raise critical funds to win Question 6 because my friends Heather and Deborah Mizeur — and every (lesbian, gay, bisexual and transgender) couple in the Free State — should be treated equally under the law,” Etheridge says.

The solicitation comes as both sides gear up for a costly ad campaign that is expected to start playing out on television in Maryland by next week.

Mizeur, who was active in the fight to pass a same-sex marriage bill this year, is considering running for governor in 2014. The bill was signed by Gov. Martin O’Malley (D) in March but promptly petitioned to the ballot by opponents.