The 33-year-old model - who welcomed her first child with Jack in 2023 - has taken to social media to confirm recent rumours that she's engaged to the 36-year-old comedian.
In a new post on Instagram, Roxy shows off her sparking engagement ring in a series of videos taken during the last two "magical months".
The model captioned the post: "How could I fit in a whole year of highlights in one video? Here is a snippet of the last 2 magical months of 2024, feeling utterly blessed [tears and stars emojis] (sic)"
Jack - who previously dated actress Gemma Chan between 2011 and 2017 - commented on Roxy's post, simply writing: "My love [heart emojis] (sic)"
The loved-up duo began dating back in 2020, and Jack previously revealed that Roxy has a "veto" over his comedy routines.
The stand-up star - who has also enjoyed success as an actor - told The Sun newspaper in 2023: "Roxy definitely gets a veto. She can be a tough crowd for my brand of humour but, touch wood, thus far she has been very accepting of me doing routines about her private life on stage."
Jack acknowledged that dating a comedian can be a "stressful" experience. But he observed that Roxy has the "patience of a saint".
The comedian explained: "It is a blessing she hasn't said no to anything yet.
"Dating a comedian can be stressful because they go up on stage and tell a load of strangers all about your private life for the sake of comedy.
"She has been very patient with it all. Roxy has the patience of a saint."