Tamzin Outhwaite has paid tribute to her trans child Flo as he celebrated his 18th birthday on Wednesday. 

The EastEnders actress, 55, is mother to Flo and Marnie, 12, with her ex-husband Tom Ellis who she split from in 2014.

The star has been open about her family's journey to acceptance after Flo came out as trans and revealed he identified as a boy when he was 'about 10 or 11'.

And as he marked the milestone birthday, Tamzin took to Instagram with a heartfelt post as she gushed over how 'proud' she is of him. 

She wrote: 'Happy 18th birthday to my incredible 1st born @floellisouthwaite who deserves all the goodness this world has to offer, and all the joy coming to him!

'I could not be more proud of you. You inspire, surprise and astound me daily.

'Your kindness, heart, dedication, determination, resilience, humour, courage, talent, work ethic, passion, grace, positivity…. (I could go on) are a joy to behold! What you have already achieved in these first 18 years is AMAZING.'

She added: 'I love you SO MUCH… Here’s to YOU my darling. May adulthood bring you peace, happiness & the success you so deserve.'

Fans were then left emotional as they spotted Flo's grandad Colin also commented as he wrote: 'I’ve feared for you for 18 years. I need never have worried.

'Thanks for educating me and being such a special grandson.xx'

Responding to the sweet message they penned: 'what a wonderful grandfather'; 'awwww what a fantastic granddad you are'. 

Tamzin had never spoken about Flo's identity until July last year when she opened up during an appearance on the Parenting Hell podcast. 

She said: 'I've got two kids. I did have two daughters and now I have a son and a daughter. That's quite easy for me to say now, but it wasn't maybe six or seven years ago.'

'The maddest thing is I suppose that it's not the most interesting thing about him,' she said. 'He's an incredibly funny, intelligent boy, and I'm watching him grow into a wonderful human who's very talented.

'To see him thriving is just nothing but relief and joy for me really because there were some dark times.' 

Tamzin recalled the period when Flo first came out as trans, which she remembers as a 'very distressing time'. 

'Until you're going through it yourself with your child, it's difficult to judge the situation,' she said.

'Initially, I would say, don't be ridiculous. I didn't say don't be ridiculous but my mind went, "that's ludicrous". 

'Working back from that with talking, family therapy, therapy on Flo's side as well, talking with family and realising you're not alone. 

'I think if you push back on a kid, they'll want to do the opposite of what their parent says. I didn't say "you can't be that", but it was a distressing time. We worked together as a family and with outside help.'    

Rob Beckett, who co-hosts the podcast with Josh Widdicombe, said: 'You can't do everything to make them happy. It's in them and there's other things at play. Having to let things take their course…'

'Yeah,' Tamzin responded. 'Time and action, but also being sensitive and, you know…. The whole LGBT community get a bit of a hard rap at the moment - it's quite tough, I think. It is a hot topic.'

Josh said: 'It's almost like you've been in sync with that topic becoming a public debate,' referring to the prominent discussion of trans issues in the media. 

'Kind of, yeah. Every situation is completely different, every child is different,' Tamzin said. 'It really is less than one per cent of the population. 

'There's this big up in arms thing. It's not that common, just because…. But I'm just so happy for him. 

'I'm happy that we're in a place and he's in a place that he is just…. I mean, he's an incredible actor. He's desperate to be a comedy writer. I was only allowed to talk about it on this podcast.'

Tamzin told how her ex-boyfriend of six years, Tom Child, is still her 'best mate' and he is always in and out of the house.

'[He] has been around for the whole of like Flo's transitioning period, for the whole of Marnie becoming a girl that was discovering all sorts of stuff and boys, and so he is still a member of the family. We've been not together for over a year. 

'The kids often say to him "When you meet someone, or even if you have, how are you going to explain this situation to your girlfriends?"'