Their second eldest son Romeo, 12, took part in the charity run on Sunday (26 April) and raised an amazing £6,000 for good causes.
And, naturally, mum, dad and brothers Brooklyn and Cruz, 10, were there to cheer him on.
Wearing 'Team Romeo' T-shirts, they watched as the 12-year-old ran the sponsored three-mile course, which is open to children aged 11 to 17.
Romeo completed the race in an impressive time of 18 minutes and 54 seconds.
Looks like dad David isn't the only athlete in the family!
After Romeo finished the race, 16-year-old Brooklyn showed his admiration by posting a picture of his younger brother with his medal for taking part.
He wrote: "Congratulations Romeo for raising £6,000 for UNAIDS and 7 Fund."
Victoria Beckham (@victoriabeckham) April 26, 2015
Meanwhile, mum Victoria gushed: "Well done Romeo!! We r all so proud!! Running @LondonMarathon for @UNAIDS and 7 Fund x vb."
Although the weather was drizzly and wet, it's clear the Beckham's didn't have their spirits dampened on Romeo's big day.
Romeo has already joined Brooklyn in Arsenal's academy and is said to be a talented tennis player.
He is also making a name for himself in the modelling world, starring in high profile campaigns for the likes of Burberry.
Victoria recently gushed about her brood on The Ellen Show, saying: "All the kids are amazing. I mean, they're really good kids. You know, they work hard at school. They're happy, they're funny.
"They're just really good kids. And Harper's so great. And the boys are great with her. She's a little tomboy. You know, she loves to wear little dresses, but then she loves to put her football boots on and get in the garden with her brothers and have a bit of rough and tumble, which I think is great."
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