The couple, who are parents to two-year-old daughter Sienna-Rae, shocked fans in March when they announced that they were set to divorce after seven years of marriage.
It's just been four weeks since Lucy-Jo spoke about her split for the first time, telling the Loose Women panel that she and Alan are "still best mates".
During the bank holiday weekend, the pair sparked reunion rumours after they were pictured openly kissing at a celebrity football match.
And they've fuelled further speculation following Alan's cute birthday message to Lucy, who turns 33 today.
Alan wrote: "Happy Birthday to my beautiful wife @LucyJo_Hudson who is 33 today. Love you so much darling, and cannot wait for Paris."
Lucy replied "#luckygirl" with tons of heart-shaped eyes emojis.
Some fans had commented, saying they were pleased to see Lucy and Alan back together, to which Lucy replied with a blowing kiss emoji.
While on Loose Women last month, Lucy said: "We're so amicable and we get on and we speak every day. He comes round for a brew. We will maintain as mummy and daddy moving forward. At the minute, our focus is Sienna."
Lucy said she was "up and down" following the split, but added: "It's difficult but we're amicable and we're talking daily. We'll remain friends and I genuinely mean that, we still care for each other. We're still best mates, we'll never ever fall out."
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