How I Met Your Mother Pics from Fifth Season Premiere

How I Met Your Mother returns with new episodes on September 21.

Aside from the hilarious quotes and one-liners that are sure to ensure that night, here's a look at what else fans can expect to see when the fifth season premieres...

• Robin and Barney attempting to keep their romance a secret;
• Ted freaking out about his first class;
• Lily and Marshall flashing back to the days of yore.

But forget these teases. If a picture is worth a thousand words, click on the photos below from the September 21 episode, "Definitions."