One Direction's Niall Horan attended the X Factor live show and later tweeted his support for contestant James Arthur, saying: "Just been to the X Factor! Everyone was so good tonight! James Arthur is incredible."
Also in the capital, Stooshe attended the Under The Bridge gig at Stamford Bridge, while EastEnders actress Preeya Kalidas graced the red carpet at the Carlakka launch dinner.
In the US, Nicole Richie was a speaker at the Annual Teen Vogue Fashion University, Helen Hunt accepted the Silver Hugo Award for her breadth of work at the Chicago International Film Festival and Russell Brand attended a benefit for The Motion Picture & Television Fund.
Elsewhere, Joan van Ark joined Knot's Landing co-star Donnas Mills at the Carousel of Hope Ball in Los Angeles, Jessica Stroup celebrated her birthday at Pure Nightclub in Las Vegas and Chris Brown had fun out and about in Beverly Hills.
See all these pictures in our gallery below:
Copyright: WENN FayesVision/WENN.com