First off, let's break down this royal (and royal-tangential) family tree for those in the back: Pippa Middleton, sister to duchess Kate Middleton, is married to James Matthews. James has a brother, Spencer Matthews, who has gotten to know the Middleton family by way of Pippa.
And it seems he and James Middleton (Kate and Pippa's dog-loving brother) are wedding-going besties.
Spencer, who's a former reality TV star, posted the Instagram from his own wedding with the caption, “Thought I’d share this fun snap of @jmidy and I on my wedding day to the one and only @voguewilliams! What an amazing weekend that was… Feel lucky every day to be married to her.”
These top hats, the perfectly timed jump, the patterned belt and loafers...
Look out, Harry and William. These non-royal brothers-in-law have some serious style.