Harry Styles' relationship with Louis Tomlinson has become ''strained''.

The 21-year-old singer is reported to have been giving his One Direction bandmate Louis, 23, the cold shoulder after he got into a Twitter spat with former member Zayn Malik online.

Harry insists Louis' actions in blasting Zayn, 22, and his producer friend Naughty Boy have damaged the band's reputation, causing a lot of tension between the pair.

A source said: ''Harry is very aware of 1D's reputation and doesn't like getting into any public scrapes, especially with other members of the band.

''It's fair to say his relationship with Louis has been strained for some time and the last couple of weeks hasn't helped matters.''

However, a band insider has insisted Harry and Louis have been able to put the spat behind them and they have continued to work side by side on 1D's new album with Liam Payne and Niall Horan.

A source told The Sun newspaper: ''Harry and Louis are working together in the studio in Los Angeles on 1D's next album. They're fine.''

The row between Louis and Zayn took place on Wednesday night (06.05.15) with Zayn blasting his former bandmate for making ''b***hy comments''.

The hunky singer, who dramatically quit One Direction in March, took to Twitter after the 'Story of My Life' hitmaker got into another heated argument with Naughty Boy, who is helping Zayn record his first solo music.

Defending his friend, Zayn tweeted: ''@Louis_Tomlinson remember when you had a life and stopped making b***hy comments about mine?''

The spat between the long-time pals, who previously insisted they would remain close despite Zayn leaving the band, erupted after Louis mocked a picture filter Naughty Boy - whose real name is Shahid Khan - used on an image of him and Zayn in the recording studio, writing: ''Remember when you were 12 and you used to think those Mac filters for your pictures were cool haha ! Some people still do HA!(sic)''