If nothing else, this Michael Ian Black-penned romantic comedy generates actual laughter, unlike Stella-mate Michael Showalter’s wretched rom-com The Baxter.

Simon Pegg (Shaun of the Dead) plays a genial but hapless commitment-phobe who vows to finish a marathon in an attempt to win back the pregnant fiancée (Thandie Newton) he fled on his wedding day. Spoiler: He succeeds!

What elevates Fat Boy above standard romantic comedy fare is, dare I say, fart jokes and short shorts — sour patches of levity amid the sweetness. It’s There’s Something About Mary with a British sensibility.

Grade: B

Run, Fat Boy, Run is rated PG-13 and in theatres now.