King arrived before the end of the loan window closing for an initial eight weeks but there is an option of doing a permanent deal with United should things go according to plan.
King told the club’s official website: “I'm very excited to get the move to Blackburn.
“They are a strong team in the championship and by coming here I want to help the team to get back into the Premier League where they should be.
“The manager was a big factor in coming here, he spoke to me, he told me about his plans and the way he wants his team to play it sounded right for me, I couldn't let that chance slip.”