He made his directorial debut with 2011's Wild Bill and most recently directed 2016's Eddie the Eagle, about the British ski jumper who took the 1988 Winter Olympics by storm.
Singer was sacked from the project on December 7, after a prolonged absence from the set.
Prior to his dismissal, the studio reportedly received multiple complaints about Singer's unprofessional behaviour, with Jim Beach briefly quitting the film and star Rami Malek getting into a heated altercation with the now-axed director.
The film has gone through a lot of snags throughout its years-long development, and for several months between 2013 and 2014, Fletcher was one of the rumored directors attached. For Fletcher, this brief taste of directing a big-name biopic acts as a precursor for his Elton John biopic that's still to come.
It was necessitated, of course, after Singer failed to return to the set in London following the Thanksgiving holiday break. It is thought that the decision "reflected a growing clash between Singer and actor Rami Malek and was caused by Singer's being missing from the set". That means Bohemian Rhapsody will hit theaters on December 25, 2018, as planned.
Singer refutes the claims that a chaotic set environment led to his departure; The director released a statement which said he needed time to care for a "gravely ill parent" as well as his own health.
Bohemian Rhapsody also stars Ben Hardy, Gwilym Lee, Joseph Mazzello, Allen Leech, and Lucy Boynton.