Barbara, 22, has previously been linked to Niall Horan, Harry Styles
and Justin Bieber
Lewis, 31, dated Nicole Scherzinger on and off for seven years
He has been linked to Kendall Jenner, Rihanna and Hailey Baldwin
By REBECCA DAVISON FOR MAILONLINE
PUBLISHED: 13:40 GMT, 19 May 2016 | UPDATED: 14:54 GMT, 19 May 2016
They've been spending the week attending various showbiz parti...