The British stars took the stage at the O2 Forum on Saturday night (26Mar16), marking the first of four shows for their hometown mini-residency.

However, hours before the show, bassist Theo took to Facebook.com to tell their fans he would not be joining his bandmates for the big concert.

"Due to unforeseen circumstances Theo (me) won't be able to play the show tonight," he wrote. "I have developed a really bad infection surrounding my elbow leaving me in considerable pain with limited mobility and on a lot of very sickly medicines. At the moment the plan is to take things day by day and see how it develops.

"Its (sic) with heavy heart that I've made this decision as every show is beyond important to me, replacing me is the brilliantly talented John (Victor) of Genghar fame, his axe slaying ability is beyond comprehension so you are in very safe hands."

He concludes, "This is something I never wanted to happen and I am truly gutted, tonight's show will still be spectacular and, fingers crossed, I will be fixed as soon as possible."

During the gig, singer and guitarist Ellie Roswell showed her support for their bandmate by urging fans to put their '"elbows in the air" for Theo and the concertgoers happily made the motion in unison.

Fans were treated with a special treat prior to Wolf Alice taking the stage, when British punk band Slaves played a surprise set at the concert.

Wolf Alice will continue with their mini-residency until Tuesday (29Mar16).