Even hardened drinker Sadie Frost can't keep up with Amy... after just three hours at Wino's

But even so, the notorious party girl can't keep up with the 24-year-old's wild ways.

Leaving Amy's north London flat after a long session, the mother-of-four was supported by on-off boyfriend Kristian Marr who helped her into a waiting car at 2.30am.

A friend of the Rehab singer, Sadie has always taken on an elder sister role with Amy  -  trying her best to keep the wayward and drug-addled star on the straight and narrow.

Sadie and Kristian were all smiles and seemed totally sober when they arrived at around 11.30pm.

Sadie Frost looks worse for wear as she leaves Amy Winehouse's Camden home last night

When they left, Sadie could barely walk and had to be helped to her waiting cab.

A source said: 'The zip of her dress wasn't done up properly and her jacket was tucked into the back of it. She was in a real state.

'Oddly, she left clutching a box full of junk, which had "all make-up/skin care bits" written on the top.'

It's not clear what happened in the four hours between Sadie arriving and finally leaving, but it clearly didn't agree with her.

She likes a party  -  but maybe she was just knackered after trying to get out of Amy's front door.

A source said: 'When they came to leave at around 2am, they couldn't open the front door.

'There were various people looking through the letterbox as they fumbled around to try and work out how to open the door.

Sadie reportedly had trouble standing up as she left Amy's home wearing a pair of the singer's trademark ballet pumps

'Amy said she had lost the key after locking it, so there was a bit of a panic as they tried to work out how they were going to get out.'

Or perhaps she was merely imitating Amy, 24, who herself arrived home from her V Festival performance the day earlier in a shockingly bad state.

She arrived at her Camden flat with filthy hands, matted hair and a grimace on her face.

Meanwhile, Sadie's red dress as she left was unbuttoned at the back and, as she slumped in the car, her underwear was clearly on show.

Unbuttoned: Sadie's dress looks uncomfortably tight

Homeward bound: On/off boyfriend Kristian Marr gives Sadie a supportive hand after they spent two hours with troubled singer Amy

Sadie stumbles out of Amy's flat, with her on-off toyboy musician boyfriend Kristian Marr

Sadie carried a box home labelled 'make up and skin care bits'

As ringleader of the bright young things of the Primrose Hill set, she once partied hard with friends including Kate Moss.

But in 2006 she announced she had given up alcohol, and appeared fresh-faced.

At the time, she said: 'I had lots of things I wanted to do and the only way I could do everything was to get rid of something and I thought that should be drinking.

'Being sober has actually been easy for me. It never bothers me if I'm around people drinking.' 

However Sadie seemed to have forgotten her words last night as she stumbled to her car.

The bleary eyed former actress carried with her a box labelled 'All make-up/ skin care bits', which appeared to hold clothing and a bag.

Amy Winehouse arrives home in the early hours of Monday morning, but just 24 hours later she was entertaining Sadie