It's never great sending a text to the wrong person, but a message intended for your ex-girlfriend going to your current one is perhaps the worst - as Prince Harry's found out.
Now's learnt Hazza accidentally sent a text reminiscing about a song he and Chelsy Davy used to consider 'theirs' to his new love Cressida Bonas.
And we've heard that the dance student was, understandably, less than impressed.
A source tells Now: 'Harry tried to cover up his mistake, but it was pretty obvious what had happened.
'He was totally mortified about it all - it was such a simple mistake and it ended up causing him a lot of hassle and heartache.'
His gaffe came after ex Chelsy, 27, got in touch with him to wish him the best in his new relationship and to say she thinks Cressida's a nice girl.
The pair - who dated on and off for seven years until 2011 - then began exchanging friendly messages, both reminiscing about the past.
However, Harry, 28, was soon regretting their innocent exchange after he wrote Chelsy a text saying he'd listened to Rihanna's track Only Girl (In The World), telling her: 'That was our song. (lol)
'It still reminds me of you.'
But when he hit send, unlucky Hazza realised that he'd accidentally sent it to Cressida, 24, instead.
Pippa Middleton's whirlwind romance with new man Nico Jackson appears to have hit a speed bump.
Now can reveal that the high-flying stockbroker, 35, wasn't happy with his 29-year-old girlfriend after discovering she'd been sending flirty texts to Prince Harry!
'Nico adores Pippa but her flirting's off the scale,' says a source.
'She often texts Harry with saucy jokes, suggesting they meet up.
'To Pippa it's just being friendly, but she told me Nico wasn't very impressed.
'They've had some big rows about it.'
Harry, who's dating Cressida Bonas, 24, will no doubt laugh it off but Pippa's now having to watch her vivacious behaviour.
Our source adds: 'Nico's asked her to tone it down.'
This post is dedicated to the royal fans of Tumblr. Keep on fighting the good fight, ladies.
Source 1& 2