New York Mayor Michael Bloomberg. (Photo by Bryan Bedder/Getty Images for NY1)

Michael Bloomberg, a billionaire who went to college at Johns Hopkins University, has donated $250,000 to the campaign to uphold Maryland’s same-sex marriage law.

The contribution, made earlier this month, was confirmed Friday morning, shortly after Bloomberg sent out an email solicitation seeking donations from other same-sex marriage supporters.

“As a business leader and Mayor of New York City, I do not believe that government has any business telling one class of couples that they cannot marry,” Bloomberg says in the solicitation, in which he notes that his state legalized same-sex marriage last year.

Bloomberg, an independent, also mentions his Maryland ties and writes that Gov. Martin O’Malley (D) asked for his help on next month’s ballot measure.

“Maryland will always hold a special place in my heart,” Bloomberg says. “I went to college at Johns Hopkins in Baltimore, and have remained active in the Hopkins community. So when Governor O’Malley asked me to support Question 6, I didn’t hesitate.”

Bloomberg’s contribution was first reported by The New York Times.

Its disclosure comes on a day when both sides in Maryland’s same-sex marriage fight will be required to report their fundraising activities to date. Reports are due at the State Board of Elections by the end of the day Friday.