Geri Horner has posted a sweet birthday message to her son on Instagram

Geri - who has Monty with husband Christian Horner, as well as Bluebell, 14, with Sacha Gervasi - wrote in her post: "Happy birthday Monty! Four today!! We love you! [kiss and heart emojis] Xxx (sic)"

In the video clip, Monty is seen running into the arms of Geri, who wishes her son a happy birthday.

Geri's house is also filled with balloons and birthday cards to celebrate the occasion.

The pop star - who has been married to Christian since 2015 - previously revealed that motherhood has helped to heal her relationship with food following her bulimia battle.

Geri has embraced a more healthy approach to food since having kids.

She said: "Food for me has been such an interesting subject so to find a healthy relationship has taken time.

"I only did 'Bake Off' because my daughter loves that show and when I did, I re-embarked on this whole journey of me re-establishing my relationship with food."

Geri's approach to food has changed dramatically over recent years.

She explained: "I realised actually you can start loving it, having fun with it, and it’s a way of relating with people - and it reminded me of when I was little and I was making cakes with my aunty Doreen.

"I had always wanted a good relationship with food so my daughter would have it, so she wouldn’t be like how I was when I was growing up - always on a diet and had no interest whatsoever.

"As a world we are moving in a different direction now anyway. Yes, we want to be gorgeous but we’re letting go of perfect. I think we’re bored of it."