Who's That Girl? Madonna looks drained as she holds 'respiratory inhaler' while taking a breather during rehearsals for Brits performance

Earnest rehearsals for a live performance at the forthcoming Brit Awards appeared to have taken their toll on pop stalwart Madonna as she stepped out on Sunday evening.

The 56-year-old will receive the Lifetime Achievement award when the annual show kicks off at London’s O2 Arena on Wednesday evening.

But as she emerged following a choreographed rehearsal at the cavernous venue, Madonna looked drained and in need of a good night’s sleep.

Earnest preparations: But Madonna appeared to be in need of a good night's sleep as she prepared for her performance at the forthcoming Brit Awards on Monday evening

The pop legend sported a casual hooded top and tracksuit bottoms as she idled outside with members of the production team after the energetic routine that will no doubt close Wednesday’s awards ceremony.

Curiously, the singer held what appeared to be a small pocket sized nebulizer – an inhaler commonly used to alleviate respiratory conditions such as asthma.

With the item held in her right hand, workaholic Madonna took a short break before resuming her preparations for the annual event.

I'll huff and I'll puff: The pop legend held what appeared to be a small pocket sized nebulizer – an inhaler commonly used to alleviate respiratory conditions such as asthma