The 20-year-old scored 23 goals in 44 appearances for Anderlecht last season and completed the formalities of his medical on Monday with just the granting of a work permit needed to rubber-stamp the deal.
He impressed in the Champions League group stages, scoring against Borussia Dortmund and in a 3-3 draw with Arsenal at the Emirates stadium in November.
The Serbia international has set his sights high, and is aiming to emulate one of the all-time greats in the black and white jersey.
He said: “There will be pressure here, for sure, but I like pressure. I also know about the famous players who have played for Newcastle United, like Alan Shearer who is a hero of mine. I hope I can play like him for this club. It will be an honour.”
Mitrovic follows PSV Eindhoven midfielder Georginio Wijnaldum to St James’ Park and new head coach Steve McClaren is delighted with his latest piece of business.
He said: “I think this is a fantastic signing for us. We’ve fought off a lot of competition to secure a top young talent in Europe.
“Aleksandar is someone who can develop with the team and someone who will help us to get to where we want to go. As a board we have worked hard to make it happen. It’s another demonstration that we are wanting to push on.”
Mitrovic has scored 30 goals in 78 in all competitions for Anderlecht since joining them from Partizan Belgrade in a club record 5m euros deal in August 2013.
Mitrovic becomes Newcastle’s fourth most expensive acquisition with fellow new boy Wijnaldum (£14.5m) third. Shearer (£15m) is in second place behind Michael Owen who cost £16m when he joined from Real Madrid in 2005.