If you got your timing wrong at Thursday night's Richard Hawley gig – a quick trip to use the facilities or order that last pint of the night, and you might just have missed one of the most surprising guest appearances of the year.

Hawley and band, currently touring the U.K. off the recent release of album 'Truelove's Gutter', had already played a beautifully bruised, hour-long set at London's Shepherd's Bush Empire to a reverent crowd, when the band returned to the stage for the encore.

Hawley, it turned out, something to tell us -- news that he and the band had been writing with a female singer and it was time the world knew about it. Dame Shirley Bassey, perhaps; Hawley is one of the songwriters who has penned tunes for the Dame's new album 'The Performance.

No. Hawley the said: "Would you please welcome to the stage, Miss Lisa Marie Presley." With no more fanfare, the King of Rock 'N' Roll's only daughter strode to the mic to sing a song, a bluesy affair called 'Weary.' Hawley didn't join her for vocal duties, instead standing back from the mic to play the song's glowing lead guitar lines.

Then, with a hug and a kiss for Hawley and a wave to the crowd, Presley was off, leaving much of the audience blinking in disbelief.

Presley hasn't released any music since a version of 'In the Ghetto' in which she "duetted" with her late father Elvis two years ago. Is a Hawley co-written album now in the works?