Portraying a real person you've never met on stage must be a daunting prospect for any actor. But having to do so in front of a theatre full of people who knew that person personally, and in many cases intimately, is a challenge best attempted only by the bravest of the brave.
Or, in the case of Robert Cargill, the most talented of the talented.
No-one who watched his performance in the premiere of The Man In The Red Scarf at the Barbican Theatre in Plymouth tonight could have considered it anything but a triumph of the highest order.
His portrayal of the artist Robert Lenkiewicz evoked not just the spirit of the late lamented painter but gave it a physical form that was a study in perfection.
The body language, posture, mannerisms, gestures and speech could not have been more accurate or convincing and could only have been rivalled if Lenkiewicz himself had been able to be there.
And as someone who spent hundreds of hours in the artist's company over many years, I had to keep reminding myself that he really wasn't.
To sit, at times, only four feet away from the actor and feel the hairs stand up on the back of your neck as you believe you're watching a man you know in reality to be dead is as good as it gets in a theatre - and physiological proof, if you like, of the actor's talent.
That's why those of us in the audience who knew Robert Lenkiewicz personally found it painful, moving and distressing to see "him" dying on stage in front of us as Death finally claimed the man who had once faked his demise in a notorious but elaborately planned publicity stunt.
Ridiculous as it might seem, as I'd been to his funeral service in real life, there were times in the performance when I questioned whether he hadn't managed to fake it a second time and reappeared to play himself to an unsuspecting audience.
Such is the magic of theatre, and the power of Robert Cargill's extraordinary performance.
The play, performed by New Street Productions and written and produced by Jojo with original music by Paul Lloyd, concentrated on the artist's relationships with women, his support for the homeless, and his larger-than-life personality.
Former Brookside actress Jill Greenacre gave a particularly fine performance in a cast of women who played multiple roles, knowing that some of the artist's lovers they were portraying were watching them from a few feet away in the auditorium. So no pressure, then!
They acquitted themselves superbly, resulting in a play that would, I suggest, have left the artist tickled pink if only he could have been there to see it.
It deserves a much wider audience. And for all those who wish Robert Lenkiewicz was still with us, this is about as near as we're likely to get.
The play runs at the Barbican Theatre until 20 December.
Jon McKnight