Little-known Canadian actor Izaak Smith and industry newcomer Chattrisse Dolabaille have been respectively cast as producer Timbaland and rapper Missy Elliott in a new Tv biopic based on the life of tragic R&B star Aaliyah.

Nickelodeon regular Alexandra Shipp recently stepped in to replace Zendaya Coleman as the late Try Again hitmaker for the film project, and now Tv bosses have found the people they want to play Aaliyah's music mentors.

More: Who is Alexandra Shipp?

Smith previously appeared in 2010's Percy Jackson & The Olympians: The Lightning Thief and 2012's Mirror, Mirror, while Aaliyah: Princess of R&B will mark Dolabaille's professional acting debut.

However, the latest casting decisions have not gone down well with many fans, who have taken to to express their disappointment, insisting slim and light-skinned Dolabaille, in particular, looks nothing like Elliott, who was previously known for her short stature and heavy frame.

One Twitter user wrote, "Whoever is doing the castings for @lifetimetv needs to be fired with the quickness (sic)... Did you even try with the Missy Elliott casting? Like you know she's like seven shades darker with hips right? #LifetimeCastings", while another joked, "Lifetime should let (basketball icon) Magic Johnson's son play Missy in the Aaliyah movie @lifetimetv #lifetimecastings".

Lifetime executives have yet to respond to the criticism.

It's not the first time the project's casting directors have come under scrutiny - Coleman faced a similar backlash when she was first picked to play Aaliyah in June (14), before dropping out weeks later.

The biopic has also been blasted by members of Aaliyah's family, who have since announced plans for their own big screen film based on Aaliyah's life story, with singer B. Simone in the lead role.

The singer was just 22 when she died in a plane crash in 2001.

More: Lifetime casts Timbaland and Missy Elliot