Katy Perry guest stars on How I Met Your Mother on Monday, February 7. Perry, the California Gurl, is supposed to be fixed up with Ted, but catches the eye of Neil Patrick Harris' Barney, instead!

Newlywed Katy Perry may be off the market in the real world, but she's brining her flirty A-game to How I Met Your Mother on the February 7 episode.

Perry plays Zoey's (Jennifer Morrison) cousin, who is so sweet and naive that the How I Met Your Mother gang starts calling her Honey.Honey actually may be more dingy than sweet, depending on who's telling the story, and comes into the picture when Zoey sets her up on a date with Ted (Josh Radnor). Unfortunately, it's no love match, especially after Ted finally realizes he's fallen for his nemesis-turned-bestie Zoey!

While Ted calls a Zoey intervention on himself, Barney (Neil Patrick Harris) zooms in like a bee to, well, Honey. Never one to leave a man hanging, let alone miss an opportunity with a hottie, he fills in for Ted and puts the moves on Perry's Honey.

Neil Patrick Harris is so excited about costarring with Katy Perry that he tweeted what he thought was a sneak peek of their How I Met Your Mother promos. "CBS just emailed me promos for the Katy Perry episode of How I Met Your Mother," Harris tweeted January 31. "Not sure if I'm supposed to tweet 'em yet. Oops."

In fact, clips and promos of Perry's stint on How I Met Your Mother were already making the rounds and no surprise, they look funny.

Perry joins the ranks of past How I Met Your Mother celeb guest stars Spencer Pratt, Kim Kardashian, Jennifer Lopez, Carrie Underwood and Britney Spears when the singer appears on the show February 7.