Harry Styles and his girlfriend have had matching tattoos.

The One Direction hunk reportedly arranged for an artist from his favourite tattoo parlour, Shamrock Social, to visit his Los Angeles home so he could prove his commitment to model Nadine Leopold.

A source said: ''Harry is having to do a lot of the running with Nadine.

''He knows what his reputation as a womaniser is like. He's desperately trying to show her he's serious about her and she's not just another girl.''

The couple - who have been dating since November - reportedly got one another's initials etched onto their bodies, but it is unclear where.

With Harry, 21, preparing to go on tour with the 'Little Things' group, Nadine, 21, has promised to join him at some shows but not at the expense of her own career.

The source told heat magazine: ''She's shooting in Mexico at the moment but she will join him on 1D's world tour for a couple of dates.

''But it'll be based around her modelling schedule. She's not following him around like a lap top and that's what's keeping Harry so interested - he's totally into her.''