The 20-year-old, wearing a strapless black dress, was joined by boyfriend Oliver Cheshire at the event. Celebrity guests showing their support included JLS singer Aston Merrygold, broadcaster Vanessa Feltz and stars from E4 series Made In Chelsea.
Lott said: "I love designing my own clothing line with Lipsy. I am so excited that this is my fourth clothing range. The new range is the best one yet."
Lott recently debuted new single 'What Do You Take Me For', the second track to be lifted from her upcoming album Young Foolish Happy.
> Pixie Lott: 'I'll never get out of control like Amy Winehouse'