Louis Tomlinson and Johannah Deakin
Louis Tomlinson described his mother Johannah Deakin (left), as his best friend Getty

One Direction star Louis Tomlinson may be grieving for his mother, Johannah Deakin, but her touching final Instagram post shows her love for him knew no bounds.

Deakin described Tomlinson as "my perfect boy" in her final update - a picture of her 24-year-old son at the Pride of Britain awards, posted five weeks ago.

The 42-year-old lost her battle with leukaemia on Wednesday (7 December), just days before the Tomlinson's scheduled performance on the X Factor semi-final this Saturday (10 December) – a commitment he is set to go ahead with as his mother's "dying wish".

Breaking his silence on Twitter ahead of performing solo single Just Hold On, Tomlinson wrote: "All the support has been incredible! Let's do this together tonight."

It is his first tweet since mid-October and his appearance on the show will be his first outside of One Direction – the X Factor boy band who went to global and success before announcing a hiatus this year.

Tomlinson has been inundated with messages since the tragic news broke, including former band tearaway Zayn Malik, who quit in 2015 to jump start his solo career.

He tweeted: "love you bro! All of your family is in my prayers. proud of your strength and know your mum is too x"

Tomlinson previously described his mother as his "best friend".

In a statement, her family said: "It is with immeasurable sadness that Johannah Deakin's family said goodbye to Johannah in the early hours of Wednesday 7th December 2016.

My perfect boy ❤️

A photo posted by Mrs Johannah Deakin (@mrsjohannahdeakin) on

"Earlier this year Johannah was diagnosed with a very aggressive form of leukaemia that required immediate and continuous treatment. We respectfully request that the family are given time and space to grieve in private."

Deakin, a charity worker and midwife, leaves behind her husband Dan Deakin, and her seven children – Louis, 24, Lottie, 18, Félicité, 16, and two sets of twins, Phoebe and Daisy, 12, and Ernest and Doris, 2.