What do the president’s half sister, actor Kal Penn and Star Trek legend slash Facebook celebrity George Takei have in common?

All of them have endorsed Rep. Michael M. Honda, who on Tuesday announced support from six Asian-American and Pacific Islander leaders.

The endorsements are a sign that the California Democrat is taking seriously a challenge from Democratic opponent Ro Khanna. An Indian-American lawyer, Khanna is the first serious challenger since Honda was first elected to Congress in 2000.

Both Democrats will battle for the Asian-American community next year. The California 17th is the first Asian-American-majority district in the country and a vital constituency for 2014.

“I’m deeply honored to be endorsed by these leaders of the AAPI community,” Honda said in a news release. “I thank them for their support and their contributions to our community and our country. I look forward to continuing to work together on issues of economic opportunity, education, immigration reform and more.”

The full list of endorsements Honda touted on Tuesday includes:

• Obama Cabinet Secretary Chris Lu
• Retired Army Maj. Gen. Tony Taguba, who authored the report on the Abu Ghraib Prison in Iraq
• Obama’s half-sister Maya Soetoro-Ng, a professor
• Star Trek actor and gay rights activist George Takei
• Actor Kal Penn, former assistant director of the White House Office of Public Engagement
• TV host and lawyer Yul Kwon