The singer was in high spirits as she arrived at popular celebrity haunt Mahiki with her close friend Lady Victoria Hervey in tow.
Once inside, the 26-year-old blonde met up with Crane, who is a DJ at the Mayfair venue, for a long evening of partying.
But all that fun proved a little much for Sarah, who eventually left the club at 3.45am looking decidedly bleary-eyed.
On again: Sarah Harding enjoyed a wild evening out at London's Mahiki with her DJ boyfriend Tom Crane last night
Sarah's on-off romance is back in full swing after a turbulent few months, with the couple now discussing marriage.
She says now: 'I absolutely love him. He’s really good for me.
'We’ve talked about marriage and all that. Everything is just perfect.'
Steady on: The Girls Aloud star looked a little wobbly as she called it a night
The pair, who briefly split over the summer, have even bought a £1million home in Princes Risborough, Buckinghamshire.
Tom added: 'We’ve spoken about starting a large family and marriage and will do so soon, when the time is right for both of us.'
Fellow Girls Aloud star Nicola Roberts was also in a party mood last night, attending a Fashion Week party at the May Fair Hotel.
Worse for wear: Sarah looked a little dishevelled as she emerged from the club
She showed off her freshly dyed bright red locks as she enjoyed an evening out with friends.
And while Sarah is considering settling down, single Nicola has no such plans following her split from Carl Davies earlier this year.
She said: 'I'm banning men. No more fellas for me. I want to be on my own.
'I've been in relationships since I was 16 and just want to be by myself and hang out with my girls.'
Girls night: Sarah enjoyed a night out with Lady Victoria Hervey while bandmate Nicola Roberts attended a Fashion Week party
