There may be more trouble ahead for Lindsay Lohan and Samantha Ronson after a meeting with producer Pharrell Williams reportedly resorted in another spat. 

The couple - who showed a united front at the Declare Yourself event in Washington on Sunday - are said to be in turmoil again over Sam's jealousy.

The DJ is rumoured to have blown her top at the sight of Lindsay's reaction to the N.E.R.D star - who wants to get his hands on the Mean Girl's musical talents.

A source tells the UK's Daily Mirror, "Sam is not usually jealous of guys but from the way Linds acts around Pharrell, it seems she thinks he could be competition."

See Lindsay and Sam in Beverly Hills below