The Red Devils sacked Jose Mourinho on Tuesday after a dismal start to the season.
Executive vice chairman Ed Woodward wanted to name an interim successor to the Portuguese coach within 48 hours.
But it now seems a website gaffe has let the cat out of the bag early.
On the club's official website, a video of Solskjaer scoring in the 1999 Champions League final victory over Bayern Munich was added with the headline saying:
"The most famous night of Ole's career."
But underneath that a caption said:
"Solskjaer becomes our interim manager, 20 seasons after clinching the Treble with THAT goal at Camp Nou..."
