Why is John Travolta's face 'melting' on American Crime Story?

John Travolta plays OJ Simpson's lawyer Robert Shapiro in American Crime Story: The People v. OJ Simpson.

John Travolta's appearance in American Crime Story has fans worried the Pulp Fiction star's face might be melting.

Travolta, 62, plays OJ Simpson's lawyer Robert Shapiro in the show, a fictional account of the the real-life murder trial of the famous footballer.

But Travolta's appearance has sparked some hilarious reactions from fans.

In the show, which screens on Sky TV's SoHo channel on Wednesdays at 8.30pm, the actor sports slicked back hair, a deep tan, bushy eyebrows and stern but camp range of comical expressions.

John Travolta in American Crime Story: The People v OJ Simpson.

Fans have asked what's happened to Travolta's face, and queried whether the star had been under the knife.

"How freaked out are you about John Travolta's face?" asked one fan.

"It's worth watching The People vs OJ Simpson just to see John Travolta try to act with his face tied behind his head," joked another.

A third compared his appearance to a Mr Potato Head toy with mix-and-match features.

John Travolta in "The People vs. O.J. Simpson" is what it would look like if we tested makeup on lions.

— Sean Brewster (@TheSeanBrewster) February 17, 2016

John Travolta preparing for his role in The People vs OJ Simpson. pic.twitter.com/YicAHSVAvv

— Matthew Sweet (@DrMatthewSweet) February 20, 2016

Has anyone seen The People v OJ Simpson? Oh my days, John Travolta's plastic surgery!

— eyegazeartist (@sarahezekiel) February 23, 2016

The AC is up high so John Travolta's face doesn't melt. #ThePeoplevOJSimpson #ACSFX

— Patti LaBelle's Nokia Flip Phone (@indoob) February 3, 2016

It's worth watching The People vs OJ Simpson just to see John Travolta try to act with his face tied behind his head.

— Nick Hussey - FRAHM (@FRAHMjacket) February 17, 2016

Watching the OJ Simpson mini series and the only thing I can focus on his how tight John Travolta's face is.
The man looks like leather.

— Jeannine (@jeanninemdenny) February 7, 2016

I would strongly advise John Travolta to avoid standing near any fireplaces...Im afraid he may melt. #HadSomeWorkDone #PeoplevsOJSimpson

— Tim (@Dangerous180) February 22, 2016

Cuba Gooding Jr, who plays Simpson in the show, told People Travolta was his favourite co-star of all time.

"Besides singing with him to entertain the gallery of the courtroom, I just enjoyed hearing stories of his life from [sitcom] Welcome Back, Kotter to travelling with Michael Jackson," he said.

- nzherald.co.nz