All eyes were on a purple bruise on Amy Winehouse's neck on Friday as she paid tribute to her incarcerated husband at a Portuguese gig.

The unsightly mark on the troubled singer's neck at the Rock in Rio concert in Lisbon left fans wondering if Winehouse was sporting a love bite from her spouse Blake Fielder-Civil.

The Rehab star's mysterious body marking appeared to suggest Winehouse had received a souvenir from her visit to Fielder-Civil at Pentonville Prison in north London just hours before flying to the Portuguese capital.

Pain in the neck: Amy Winehouse had a visible dark-looking bruise as she performed

The singer arrived at the gig half an hour late and croakily admitted she was suffering from a sore throat as she attempted to make amends to the 90,000 fans at the Bela Vista Park.

Friday marked Winehouse's first concert performance since she cancelled a series of gigs last November after her husband was first imprisoned.

Declaration: Amy Winehouse sports her Blake badge at a comeback concert

After finally walking on stage, a dishevelled Winehouse, admitted she probably should have cancelled the gig when she was greeted by boos.

She said: 'Hey Lisbon, I'm sorry I late.

'My voice is not singing right and I can't even hold the microphone.

'I should have cancelled, but I wanted to be here so much.'

During her performance, which finished on time despite the tardy start, the 24-year-old touched her neck repeatedly, suggesting she was conscious of the so-called love bite.

Her  voice cracked during the 55-minute set and she dropped her microphone several times.

She paused to talk to members of her band, sucked throat lozenges, and at one point dashed off stage but quickly returned.

During the gig, Winehouse made repeated references to her husband of one year.

As well as a heart-shaped 'Blake' tribute in her hair, Winehouse changed the lyrics of Cupid from 'I love a girl who doesn't know I exist' to 'I love a man you know who's banged up in jail'.

She also told the crowd her husband was 'still the handsomest bloke you've ever seen in your life'.

Just hours before taking to the stage, Winehouse made a whistle-stop visit to Fielder-Civil at Pentonville, where he has been in remand since November while he awaits trial for grievous bodily harm and attempting to pervert the course of justice.

As well as her bruised neck, Winehouse was also sporting a bandage on her right hand.

With her bruised neck and her arm bandaged up, the star seems to have been through the wars recently

She declined to say how she injured her hand, but a window in the singer's north London flat had been broken in the early hours of Thursday morning, where she had been partying with controversial friend Pete Doherty.

In a statement, her spokesman said she had been overwhelmed by the crowd's reaction at the Rock In Rio concert.

'Amy was overwhelmed by the goodwill shown by the audience in Lisbon and even apologised for her below par vocals on stage, after suffering from a sore throat all week,' he said.

'She was given the option to cancel, but was determined to take her first step back on to the live scene and although her throat was not at 100 per cent, Amy felt it important for fans to see that she is back working at her craft.

'She will continue to her comeback at events throughout the summer.'

Did a broken window at her London flat causes Amy's wrist injury?

The soul sensation - who has dismayed fans with her erratic behaviour in recent months - is due to perform a string of gigs throughout the summer.

She will appear at the Nelson Mandela Concert in Hyde Park later this month and then Glastonbury two days later, as well as festivals in Scotland and Ireland in July.

In August, she will play the V Festival followed by Rock En Seine in Paris and Bestival on the Isle of Wight.

Last month, the singer was cautioned by police over an alleged assault.

Two weeks ago she was told she would not face charges over a video that appeared to show her smoking a crack pipe.

She cancelled a series of concerts last year and postponed a tour of the US and Canada.

At the time, this was blamed on her husband's arrest.

Back to Black: Winehouse was back to what she does best despite a sore throat and performed the full set