The former Desperate Housewives actress is to call for US President Barack Obama's re-election during the three-day convention in Charlotte, NC.
Former US President Bill Clinton, Chicago Mayor Rahm Emanuel, former presidential candidate John Kerry and Obama himself will all speak from September 4 through to September 6.
Longoria has long been a supporter of Obama, having been named the campaign's national co-chair in February.
She has also contributed significantly to Obama's re-election efforts along with Leonardo DiCaprio, Steven Spielberg, George Clooney and Ellen DeGeneres.
Obama's political rival Mitt Romney will host his own Republican Party's National Convention in Tampa, FL next week.
Watch Eva Longoria appear in a Barack Obama campaign ad below: