Britney Spears stormed the set of U.K. talent show The X Factor on Saturday night - marking her first performance on British soil in four years.

Following televised turns in Germany and France the previous nights, the star took to the stage of the Simon Cowell-fronted singing competition to perform her hit single Womanizer.

Wearing black hotpants and fishnet stockings, the star appeared to have gained in confidence as she shoved male dancers about and lip-synced a remix of her song.

When asked by the show's host Dermot O'Leary if she had any advice for the contestants, the star said: "Good luck - and just keep doing it!"

Spears then reportedly ventured to London nightclub Heaven, where her triumphant comeback took an unexpected downturn when police were called to handle the overcrowded venue.

According to fan reports on music website Pop Justice, hundreds of devotees flocked to the nightclub to catch a glimpse of Spears - but were disappointed when they were told she would not take the stage.

A partygoer explains, "...I was standing in the middle (and) I was feeling badly crushed and couldn't move. People were trying to get out but there was really nowhere to go. Everyone was pushing on each other and it was becoming more and more horrific.