Virginia Gov. Bob McDonnell, right, talks with the media in Richmond in this November 2012 file photo. (Bob Brown/Associated Press/Richmond Times-Dispatch)

A Virginia state delegate has confirmed that he’s been called to appear next month as a witness before a federal grand jury as part of an investigation related to Gov. Robert F. McDonnell.

Del. David Ramadan (R-Loudoun) declined to comment further, saying that the federal subpoena prohibits him from disclosing its details, which might reveal what authorities are seeking from the first-term legislator.

The Washington Post has previously reported that the FBI has been conducting interviews about the relationship between McDonnell (R) and his wife and the chief executive of a dietary supplement company who paid for the catering at the 2011 wedding of the governor’s daughter. The agents are exploring whether McDonnell assisted the company in exchange for gifts.

Ramadan’s subpoena, however, is the first public indication of the impaneling of a grand jury to review evidence in the McDonnells’ case — a significant escalation in the investigation.

U.S. Attorney Neil H. MacBride did not return a call seeking comment. A spokesman for his office declined to comment. McDonnell’s spokesman, Tucker Martin, also declined to comment. “This office does not comment on any potential investigation,” Martin said.

David Ramadan. (Courtesy of David Ramadan)

Ramadan, a jeweler and friend of the governor’s, confirmed that he has been asked to testify before a grand jury in July to provide information that appeared to relate to McDonnell and his wife, Maureen.

“I’m cooperating and look forward to continuing to cooperate 100 percent,” Ramadan said.

How Ramadan might fit into the McDonnell investigation is unclear. It’s also unclear what precisely the grand jury is targeting and whether it already has been impaneled or won’t be until Ramadan’s testimony next month.

Ramadan said he has no connections to Star Scientific or its chief executive, Jonnie R. Williams Sr., who paid the $15,000 catering bill at the June 2011 wedding.

But Ramadan said he was a guest at the wedding of Cailin McDonnell, held at the governor’s mansion.

“Like everybody else who attended, I gave a gift,” Ramadan said. Ramadan declined to say what he gave the bride and groom but indicated that it was not money. He also declined to say whether he has ever provided other gifts to members of the McDonnell family, including Maureen.

State law in Virginia allows elected officials to accept gifts of any value provided they annually disclose all those worth at least $50.

Previous Washington Post coverage of Gov. Bob McDonnell and ties to Star Scientific.

McDonnell’s annual financial disclosure forms show no gifts from Ramadan. But the law does not require that elected officials disclose gifts provided to spouses or other members of their immediate families.

Asked several weeks ago whether he had ever given jewelry to Maureen McDonnell, Ramadan said: “It’s not something I’d like to comment on. Our current laws exempt family. This is beyond the scope [of the law] at this point, and I really don’t think we should be going there at all.”

In addition to the federal inquiry, Richmond Commonwealth’s Attorney Michael Herring has confirmed that he is conducting a parallel review of McDonnell’s annual financial disclosures to determine whether they comply with state law.

An international consultant and businessman, Ramadan is a close political ally of the governor.

McDonnell appointed Ramadan to the George Mason University Board of Visitors in 2010 and recorded a video urging support for him before Ramadan’s November 2011 election to the House of Delegates from a district representing parts of Loudoun and Prince William counties.

McDonnell’s political action committee contributed $40,000 to Ramadan’s 2011 campaign.

McDonnell has said he did not need to disclose the catering provided by Williams because it was offered as a wedding gift to his daughter, not as a gift to him. People familiar with the investigation have said that the FBI has been investigating additional gifts provided by Williams to first lady Maureen McDonnell.

Three days before the wedding, the first lady flew to Florida, where she spoke to doctors and investors interested in Star Scientific’s new dietary supplement, and said she believed it could be used to lower health-care costs in Virginia.

Three months after the wedding, she organized a lunch at the governor’s mansion to mark the formal launch of the company’s new non-FDA-approved pill, Anatabloc. The governor attended that event — he has said to recognize grants awarded by the company to Virginia universities — despite concerns from top aides that the gathering might not be appropriate.

He said last week that he has never provided special benefits to Williams or Star Scientific.

“I think what’s important to note out of all of this that’s been lost completely is that neither Star Scientific nor any other company gets any special consideration when it comes to economic development benefits or anything else,” he told reporters after a small-business forum in Richmond.

“To my knowledge, in all the research we’ve done of [the] company, Star Scientific and Mr. Williams have not gotten any economic development grants or any appropriations or any appointments or anything else from our administration,” he said.

Laura Vozzella contributed to this report.