The 27-year-old actress, who recently appeared in James Franco's fictional and trippy short story for Vice, wore a short tuxedo-style sheer black dress as she arrived at the event in the capital to open this week's London Collections: Men.
She was joined by Jessie J, who wore an '80s-style, pastel-coloured blazer with matching shorts, and US actor Jesse Metcalfe with girlfriend Cara Santana, who turned heads in a white suit.
Nick Grimshaw, DJing at the after-party, and 18-year-old model Rafferty Law - son of Jude Law and Sadie Frost - happily posed for photographers at the bash at One Embankment.
Saturdays singer and model Mollie King, looking chic in a gold lace dress, was also in attendance.
Lohan then headed to current favourite celebrity haunt Chiltern Firehouse in Marylebone.
The star has been in London to promote her documentary Lindsay, created by Oprah Winfrey's network OWN, with reports claiming she could be about to settle over here.