The 16-year-old first met Millie, 15, at Unicef’s 70th anniversary gala in December 2016, when she handed out an award to his dad David, 43.
Millie and Romeo had instant chemistry, with the actress making her feelings for the tennis hopeful very clear before the evening had even begun.
When asked on the red carpet what her hopes were for her Stranger Things character Eleven, she said: ‘I don’t know. Something with Romeo Beckham.’
And after their meeting she shared a snap of them posing together online, confessing she would ‘remember this evening for the rest of her life’.
Now the pair are reportedly dating, with a source telling The Sun it’s ‘early days’ for the duo.
‘Romeo and Millie are hanging out. It’s early days but they make a very sweet couple,’ an insider revealed.
‘Posh has given it the seal of approval as she is a big fan of Millie’s.’
The young actress boasts a string of A-List pals including Zac Efron and rapper Drake, but she is also close with Romeo’s older brother Brooklyn’s girlfriend Hana Cross.
Romeo has yet to have a public romance, but Millie was in a relationship with American singer Jacob Sartorius, 15, until July 2018.
Millie took to social media last summer to reveal they had decided to break up, but insisted they would remain friends.
‘The decision with Jacob and I was completely mutual,’ she wrote.
‘We are both happy and remaining friends,’ she acknowledged before ending the statement with a red heart emoji.
CelebsNow has contacted representatives for Millie and the Beckham’s asking for comment.