It would have been Whitney Houston's 51^st birthday on Saturday and the singer who tragically passed away in 2012 was very much on the mind of her only daughter, Bobbi Kristina.

The 21-year-old shared her love for her mum on Twitter and retweeted adoring messages from fans of the late superstar.

"GoodMorningWorld ! & AGrandBeautifulPhenomenalWonderful HappyHappyHappyBirthday2my amazingMommy! 2day is YOUR day, Iloveulady! @nickdgordon," she tweeted.

She added in another: "Love is such a beautiful thing when it's #Real."

Bobbi Kristina also posted several touching photos, among them one of a candlelit birthday cake, and another of her as a toddler with Houston.

Life has seen some huge changes for Bobbi Kristina in the last few years. She was just 18 when her mother died on 11 February 2012, and earlier this year she announced her marriage to Nick Gordon, who was cared for by Whitney as a child.

Their union was controversial because of their close childhood connection, but Bobbi Kristina has always defended it as the two are not biological brother and sister, and Gordon was never formally adopted by Houston.

There were concerns in the wake of Houston's death about Bobbi Kristina's emotional wellbeing but she appeared in good spirits over the weekend, tweeting several inspirational messages.

"I thank God everyday 4the blessings he's set upon me. Feeling #STRONG in my own shoes. Journeying alone, Feeling more comfortable then ever," she said in one tweet.

And in another, she wrote: "The beauty of life is within you,only YOU control the life God gave you.#Destiny is meaning, a SpecialUnknownJourney of ur own life ahead."

Her faith in God is something she shared in common with her mother, whose last movie appearance before her death was in the TD Jakes-produced Sparkle, in which Houston played a churchgoing single mother doing her best to raise three daughters with biblical values against the backdrop of Motown's heyday.

Houston was best known for hits like "I will always love you" and "How will I know", but her music career was pre-dated by singing in church and her final studio album was the 2009 gospel-flavoured, I Look to You.

And Bobbi Kristina has frequently tweeted about how blessed she feels to be married to Gordon.

Earlier in the month, she shared: "#HappiestMOSTconfidentsecure I haveEVER been within my life. PraiseGod everyday4thereason4 my happiness @nickdgordon"