Justin Bieber doesn't know if he's ''ready'' for a relationship.

The 21-year-old star split from on/off girlfriend Selena Gomez last year and has since been linked to pals including Kendall Jenner and Hailey Baldwin and Playboy model Xenia Deli and although he insists he's currently unattached, he's not sure if he's ready for a committed relationship.

Speaking on 'The Ellen Degeneres Show', he said: ''I'm single ladies, and ready to mingle ... But I'm in a place now ... I don't know if I'm ready for a relationship right now.''

Justin also agreed with chat show host Ellen when she suggested Madonna had been flirting with him when they appeared on the show together earlier this year.

He added: ''She was right? I felt that.''

Meanwhile, although the 'What Do You Mean?' hitmaker may not be ready to start dating, he is enjoying using Instagram to look at ''pretty girls''.

He told New York's Z100 radio station: ''Instagram is about dudes looking at pretty girls, that's basically it.

''I'm just saying that, of course girls like looking at dudes, but it's not the same as how much dudes like looking at chicks.''