The 28-year-old Norwegian international popped up as a last-minute option to help augment a Manchester United attacking line that had been robbed off the services of top scorer Marcus Rashford.
The Red Devils were reportedly quoted a transfer fee of £40m by Bournemouth but the two teams were £20m apart in their valuation and the deal stalled.
Manchester United instead went in for former Watford and Nigeria striker Odion Ighalo from Chinese Super League side Shanghai Shenhua on a deal until the end of the season.
Had the deal been completed, King would have made a return to Old Trafford, where he first signed as a 16-year-old from Norwegian side Valerenga in 2008.
King failed to make a single league appearance at United and after a series of loan spells away, left permanently for Blackburn Rovers in January 2013. He joined Bournemouth 18 months later.
King has turned his attention to helping relegation-threatened Bournemouth beat the drop, but has admitted a second chance at United would have been a ‘dream come true’.
"How close it was I have no complete answer to," King told Norwegian broadcaster TV2. "I have to watch what I say.
"I had some faith that it was going to happen and it was a bit sensitive for me considering that I moved to England as a 16-year-old to achieve my dream and wanted to reach that goal at Manchester United.
"When you hear that you are connected to United and a bid comes in, then the feelings you had as a 16-year-old come back to you.
"But why it did not happen, I do not know. I'm a Bournemouth player and I really enjoy it here. But it had been a dream come true, I will not lie.
"That didn't happen and I'm going to give everything to Bournemouth as long as I’m in this club."
One of King’s three Premier League goals this season was a winner against Manchester United in November.
