Fall TV Preview

How I Met Your Mother Season 8 Preview Video: Uh-Oh, Quinn Learns Barney's Big Secret!

Barney Stinson, you have some explaining to do! A fresh promo for Season 8 of CBS’ How I Met Your Mother, premiering Sept. 24 at 8/7c, reveals that the recently engaged former cad has been keeping a big secret from his fiancée, Quinn.

RELATED | Saturday Night Live Alum Abby Elliott Hits the How I Met Your Mother Lode

Meanwhile, the ex-bachelor isn’t faring so well at his future wedding to Robin, either. Quick, someone glue that window shut!

Check out the preview below, and then hit the comments with your thoughts.