Stephanie, who is the sister of Spencer Pratt, walked the red carpet with Spencer at a Formula 1 event in London last week, prompting rumours that there is a new reality romance in the air.
But on Friday night (28 June), it was fellow MIC star Jamie that Stephanie was seen partying with in London.
Stephanie and Spencer's best friend Jamie - who is dating Tara Keeney - were seen enjoying dinner with friends at The W Hotel before heading to 2&8 Club in Mayfair.
Spencer, meanwhile, was away in Hull fulfilling a personal appearance.
Stephanie tweeted at him: "DON'T CHEAT ON ME TONIGHT! @SpencerGeorgeM IM SERIOUS!"
Spencer, who cheated on ex-girlfriend and castmate Lucy Watson while in Greece, replied: "Of course I won't sweetie… not my style ;)"
Despite his ladies' man past, it seems Spencer and Stephanie's relationship has the seal of approval from Stephanie's sister-in-law Heidi Montag.
Heidi tweeted: "@SpencerGeorgeM @stephaniepratt cutest couple ever! We will have Christmas in Colorado this year! Xo."
Spencer replied: "Happily."
From Spencer & Lucy's split to TOWIE drama, the big stories of June in pictures:
Copyright: Twitter Kim Kardashian