Since the inception of Instagram, it's customary to share sweet birthday messages to celebrate a loved one's special day - especially when it comes your sibling.
And no matter how famous you are, when it comes to Instagram - celebrities are just like us.
Over the weekend, songstress Kylie Minogue posted a series of gorgeous throwback photographs in celebration of Dannii's 48th birthday.
"Happy, HAPPY birthday to my lil sis @danniiminogue 🎈🍰...," Kylie penned in the sweet post.
"My mind floods with so many memories - from making fun and games out of nothing when we were little, our connecting wardrobes when we were teens (imagine!!! 😳🤪😂), all the hours you put in to work at such a young age and you, me and our brother Brendan all being so fortunate to have our family and each other. I could go on and on!!! In short, I love you and I'm so proud of you Mama!!! 💖 Happy birthday!"
The caption was accompanied by four photographs, including a very smiley picture of the sisters on their front porch during their schooling years, and another of Kylie and Dannii performing on stage together at the Royal Albert Hall in 2015.
A third photograph showed the very famous pop-stars sitting on a porch wearing some ab-fab roller-blades - a photograph which we've actually seen before.
Back in May, for Kylie's birthday, Dannii took to Instagram to send birthday wishes to her older sister for her 51st birthday.
And to celebrate the big day, the pop princess put up a seventies-tastic throwback of the pair - the very same one.
"Happy Birthday to my big sister Now for a new year of fun and festivities. Love from Sister Disco xx," she captioned the pic.
Naww, how cute!
While there have been rumours of rift between the pair for many years, if these posts are anything to go by, Dannii and Kylie are as thick-as-thieves.
During a 2017 interview with Now to Love, when Dannii was about to embark on a tour with Take That, she revealed that her sister was her biggest fan.
"If she is here [in Australia], she will definitely come along," the popstar said at the time.
"She messaged to say she's so excited about it but I don't know what her plans are because she's writing her album now."
Speaking to TheFIX in 2017, Dannii revealed, "My sister's always been incredible. [She's] always a tower of strength, and very classy with how she handles everything.
"My sister is my go-to for advice. And always when I look at her, she's physically a tiny little thing, and you just think 'Where does all this strength come from?'"
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And then, back in 2015, the singing sisters paired up for a rather sparkly duet on X-Factor Australia, the first time they have performed together on television since 1986.
Back then it was for Young Talent Time, where decked out in sequined blazers, they belted out Sisters Are Doin' It For Themselves.
This time Dannii, who was a judge on the Australian talent show, stepped on stage for a duet with Kylie on their new Christmas song 100 Degrees.
The single, celebrated the hot Aussie festive season rather than a snowy wintry one, and featured on Kylie's Christmas album, appropriately titled Kylie Christmas.