Former Trump White House press secretary Sean Spicer says the Harris campaign’s decision to line up an interview with Fox News is an act of “desperation”.

Fox News revealed on Monday local time the Vice President will attend her firstever sitdown interview with the network on Wednesday (Thursday AEDT) in Philadelphia.

“They are throwing mud at the wall at this point ... they are doing whatever they can,” Mr Spicer told Sky News host Andrew Bolt.