Sen. Barbara BoxerBarbara Levy BoxerThe ‘bang for the buck’ theory fueling Trump’s infrastructure plan Kamala Harris endorses Gavin Newsom for California governor Dems face hard choice for State of the Union response MORE's (D-Calif.) campaign reached out to Republican rival Carly Fiorina for help this week -- but not on purpose.

Boxer's fundraising team sent an invite to Fiorina's personal e-mail asking her to attend the campaign's May 25 event with President Barack ObamaBarack Hussein ObamaFormer GOP lawmaker says Obama got elected because he was black To woo black voters in Georgia, Dems need to change their course of action 2018 midterms: The blue wave or a red dawn? MORE in San Francisco.

The invitation states, "With the June Primary upon us, Sen. Boxer needs to be prepared to face the 'fight of her life.' Your support is critical."

It offers prospective donors who raise $20,000 the chance of attending a 'private clutch,' presumably with Boxer and Obama.

Fiorina won't be able to make it, according to campaign spokeswoman Amy Thoma. "Sadly, she'll have to decline as she'll be out giving Boxer the [above] referenced 'fight of her life.'"

The Boxer camp confirmed the e-mail was authentic but noted it went to "thousands" of people.

Fiorina wasn't the only Republican on the list -- her campaign manager, Marty Wilson, got the invite last week.