You would have to have a heart (and loins) of granite not to melt at the radiance of Marilyn Monroe, as captured in the National Portrait Gallery’s irresistible new exhibition. On my way there, I had felt melancholic: for all the vivacity she brought to such films as Some Like It Hot, Monroe is fixed in aspic – and indeed in tasteless, widely circulated photographs of her lifeless body – on the day of her death, August 4 1962, aged 36, following a barbiturate overdose. Yet, within seconds of walking through the gallery doors, my sorrow had evaporated.

The curators’ masterstroke is to immerse us early in Philippe Halsman’s Jumpology images from 1959, which show Monroe leaping for joy with the naughty exuberance of a St Trinian’s schoolgirl. The photographer believed that jumping freed his subjects from their social personae, revealing a more authentic self. Another Halsman shot, of Monroe in jeans, reclining on an exercise bench while lifting dumbbells, proved equally captivating. It also made me reflect, in the spirit of a Rigby & Peller saleswoman, that there was no way this Hollywood goddess was a 36D cup, as history tends to record. In terms of modern lingerie, she looked, for much of her life, closer to a 30C or D.

Equally enchanting are the poetic black-and-white “mood” photos taken by André de Dienes on Malibu Beach in 1946, when the star was still known as Norma Jeane; before the beauty spot, kohl, platinum waves and scarlet lipstick became her mask. Here, her hair is a mass of tousled curls, her cheeks have the soft swell of a teenager, and an army blanket is draped over her shoulders. Harder to dwell on is the image where Dienes asked his young model to convey “death” and she placed the blanket over her head.