Willow Smith: 'Dreams do come true'

Willow Smith has said that "dreams do come true" after performing in front of thousands of fans in London.

The ten-year-old daughter of Will Smith and Jada Pinkett Smith played at the O2 arena on Wednesday night as part of her opening slot on Justin Bieber's world tour.

"London, was sooooooo AWESOME!!!!! (sic)" she wrote on her official Twitter account. "They made me feel like I am the only girl in the world... 18,000 people on the other side of the mic... dreams do come true."

Bieber took to his own Twitter feed to praise his tour mate, writing: "Just heard lil sis @officialwillow KILLIN IT on stage!! it's her first tour and trust me she is the truth! now it's my turn. LEGGO!"

Smith, who was spotted shopping at Hamleys Toy Shop in London with Bieber this week, recently released the music video for her second track '21st Century Girl', which follows the worldwide success of debut single 'Whip My Hair'.

"To be a 21st century girl means that you're practicing at what you want to do, and that you're being adventurous, and you're being confident, and you're being yourself," she told ET earlier this month.

She will support Bieber at the last of his three London dates tonight, before the tour moves onto other destinations in the UK and Europe.