Rating: Two out of five stars 

From cabaret acts and singing telegrams to Madonna's Material Girl, the world has never been short of Marilyn Monroe impersonators.

Now it's the turn of pop singer Pixie Lott to pull on the blonde wig, pearl necklace, white dress and red lipstick. And boy is she a ringer in this new play by American writer Sharleen Cooper Cohen.

The author, however, has big ambitions. As the title suggests, Cohen doesn't believe Marilyn took her own life in a tragic overdose in 1962.

It was Hollywood, the Press, the Mob, the FBI and even the CIA what done it. For Cohen, the official version of a drug overdose is all the more suspect for being well supported by facts.

In a play that has all the drama of a Wikipedia entry, we learn that it was thanks to an affair with President

John F Kennedy, and later with his brother Bobby, that Marilyn was murdered: she knew too much.

With the help of the Mob, and the cover of Marilyn's addiction to pills, FBI Chief J Edgar Hoover made sure she was taken out – and cleaned up by later knocking off JFK, Bobby and others. If Cohen is right, she'd better watch out too.

But for all the plot's febrile fiction, Lott makes a good fist of her role in Philip Wm. McKinley's zestless production, despite overusing her famously breathy, rising intonation famous from films such as Some Like It Hot.

She is also over-dependent on flirtatiously running hands down her thighs while bending legs and winking. 

Such moves only reinforce the Marilyn myth and never really get behind the mask. 

Even so, Lott toils to the end of the 140-minute pot boiler, talking us through Marilyn's lively celebrity sex life as if from the grave.

And her impersonation does become increasingly emotionally charged – culminating in a psychological epiphany with her shrink. 

The venue itself is a former cabaret club renamed the Emerald Theatre on the Embankment in the West End of London and it is tarted up like a high-end brothel. 

It's hardly the sort of place for a serious reappraisal of stereotypes and deep state cover-ups. 

The performance is much more likely to sauce up whatever we already believe.