Stephanie's grandad Albert Mulvaney passed away last October, and the actress had spoken about their close bond to her housemates including Megan McKenna.
Marking his birthday today (26 February), the Hollyoaks star posted a photo via Twitter and said: "Happy birthday to my hero and best friend my grandad! I love you so so much and miss u more every day. Heartbroken."
Happy birthday to my hero and best friend my grandad! I love you so so much and miss u more every day heartbroken pic.twitter.com/CrUSO9GslY— Stephanie Davis (@Stephdavis77) February 26, 2016
Stephanie finished in second place on the 17th series of CBB, which wrapped up earlier this month.
Her mum and dad, Pauline and Roy, had told the Liverpool Echo in January that Steph decided to sign up for CBB after getting a sign from her grandad.
Pauline said: "She was devastated when he died and she hung back after we buried him because I think Big Brother was on the horizon. She said to her grandad 'Give me a sign, should I do Big Brother or not?'
"The songs playing at the burial were 'Look For Me In Rainbows', and 'Rainbow' by the Liverpool singer Russ Hamilton, who my dad loved. When she went outside to take the phone call from Big Brother she saw two rainbows so she took it as a sign."
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