The couple joined a host of celebrities at An Evening with Pixie Lott at Langham Hotel in London, where Pixie was launching her third self-titled album.
Pixie performed an intimate set of her latest tracks and hit singles to a crowd, and later cuddled up to Millie and Pro Green while toasting her new release.
Millie and Pro Green - real name Stephen Manderson - did some celeb spotting too, and grabbed a photo with The Inbetweeners star Simon Bird!
Simon had earlier spent his evening at the premiere for The Inbetweeners 2, which was held at Vue Cinema West End, before heading off to Pixie's party hosted by Pandora.
Referring to his character's name, Will McKenzie, Millie simply said: "My hero #Will #Inbetweeners."
Former Made In Chelsea star Millie showed off her slender frame and tanned pins in a black crop top, black leather shorts and a lace cardigan teamed with strappy black heels.
The star looked to be in a joyous mood as she left the venue while holding on to her husband, and they were later photographed taking a selfie with a fan.
This week, Millie hit back at online trolls who criticised her while sunbathing topless on holiday in Ibiza.
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