It seems the pooch doesn't like to share the Olympic medallist and wasn't too happy to see Lucy cuddling up to her man for a photo opp, yesterday (26 July).
Instead of snuggling into the selfie with the good-looking couple, little Luna decided to mark her territory by biting Lucy as Louis took the snap. Cheeky!
Taking to Instagram, Lucy shared the funny photo of the trio with her fans. In her snap, she can be seen clutching her hand as Luna's gnashers take a nibble, while Louis obliviously continues to pose for the camera.
We shouldn't laugh, but seeing as Lucy still has a smile on her face, we reckon it's ok, right?
Alongside her post, the 23-year-old said: "Family photo gone wrong!! Luna decides to attack me as we take the photo! Naughty puppy!"
And it seems that wasn't the only time naughty pup Luna decided to play up...
Tweeting yesterday evening, Louis shared a series of laughing emojis as he told fans: "Haha I'm upstairs and I can hear @lucy_meck struggling to control my dog "Stop,stop. No Luna!! Ouch!! Behave! Stop! Sit."
Haha I'm upstairs and I can hear @lucy_meck struggling to control my dog "stop,stop. No Luna!! Ouch!! Behave! Stop! Sit"— Louis Smith MBE (@louissmith1989) July 26, 2015
Despite their rocky start, though, it seems Lucy finally managed to charm Luna and get her on her side.
In a total turnaround, Lucy and Luna were pictured puckering up in a new Instagram the online fitness guru shared to her Instagram feed earlier today. She said: "At @louissmith1989 chilling with Lunies."
Seems like a perfect time for that family photo, round two, no?
Lucy and Louis first confirmed they were an item earlier this year, following speculation the pair were dating. The pair initially met while both starring on BBC's gymnastics competition Tumble, although love didn't blossom between the pair until after the show.
Since then, the pair's romance has gone from strength to strength and Lucy and Louis are often sharing smitten selfies for their followers to see.
While Lucy has declared her beau to be "the best boyfriend ever", Louis has hinted he is looking forward to a long future with his reality star love.
Last month, Louis suggested babies could be on the cards for the couple, admitting: "Lucy is a big part of my life now.I don't know where that's going to go, but hopefully it will be a situation where I've got some little Lucys running around."
Eek! Sounds like things are getting pretty serious.
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