The pair, who were first romantically linked earlier this month, tried to avoid the paparazzi as they left Japanese restaurant Zuma around 10.15pm yesterday (March 12).
The Tottenham striker supported Burke at the weekend, when she performed at London's G-A-Y. Reports said the couple spent time in the club's VIP section afterwards.
Defoe also tweeted his support for the X Factor star's new single 'Elephant', referring to the 23-year-old as "my girl". Burke also had Defoe speak to fans during a uStream broadcast earlier this week.
Continuing promotion this morning, the singer was photographed leaving ITV studios in London after performing on This Morning.
Appearing on the daytime magazine show, presenter Phillip Schofield teased that Burke was attracted to an older man, highlighting her new relationship. When the host said the footballer was 30, she corrected him, laughing that he is actually 29.
Referring to the ex-boyfriend whom 'Elephant' was written about, she said: "I'm still friends with the guy I was seeing last year. I had to tell him. He knew it was about him."
> Alexandra Burke: 'People think I'm a bitch'
> Alexandra Burke covers Rihanna's 'Talk That Talk' - watch video