The 'Gunpowder' actress has been in a relationship with the sports and entertainment agent since 2014 and they became engaged in 2015.
'Fresh Meat' actor Jack enjoyed a night out with Liv and took to Instagram to tease Dave about how much fun the pair were having and casually described Liv as his pal's ''wife''.
Along with the photo of the pair partying, Jack, 29, posted: ''When your knob of a friend's wife has more fun with you than him. @davidgardner the king of the melts.#knobhead (sic)''
Liv, 40, and Dave have a two-year-old son Sailor together and a 23-month-old daughter Lula and raise Liv's 12-year-old son Milo with her ex-husband Royston Langdon and Dave's 10-year old son Grey from a previous marriage.
The family live in London's Primrose Hill, while Jack lives in south London
Liv - whose father is Aerosmith singer Steven Tyler - has been very open about how happy she is with Dave and has described their love story as an ''adventure''.
She recently said: ''I'm so in love and happy right now ... I've always been quite lucky in love. But you don't just meet someone and fall in love and live happily ever after. That doesn't exist. You meet someone and you fall in love, and then you begin an adventure.''
Despite Jack's possible slip up, the 'Super' actress previously insisted she was in no hurry to get married.
Liv told the Mail On Sunday newspaper's You magazine last October: ''It's so sweet to enjoy this stage of being together. I am not a woman who is obsessed with having a wedding - and because we aren't married yet, he has to keep asking me. I just say, 'Maybe.' ''
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