The news of Britney Spearsupcoming appearance on How I Met Your Mother shocked not only the public, but the show’s stars as well.

"I was shocked that Madame Spears was willing to come and do some acting! She hasn’t acted in a while," Neil Patrick Harris, who plays the womanizing Barney, tells Entertainment Tonight.

Nevertheless, the Emmy-nominated actor thinks Brit would do well on the sitcom with her "very interesting role." Confirming early reports that the 26-year-old is playing a worker at Ted’s (Josh Radnor) doctor’s office, Neil provides a tad more detail.

"She plays the secretary to another girl that Ted is after," he says. "It will be very unlike any Britney we have seen before, and we have seen a lot of Britney recently."

But don’t expect to see a lot of Britney on set. Because the CBS hit films on a closed set, the 34-year-old doesn’t expect to deal with the swarm of paparazzi that follows the pop star everywhere.

However, he does consider the idea that the onslaught of paps and her year-long erratic behavior are not at all what they seem to be.

"What if she shows up on set and she is absolutely, totally normal and that whole thing has been a big ruse? She is smoking a cigarette and [says], ‘Oh yes, it is all a big bit. I have a master plan.’"

For more on Neil, tune in to ET tonight!

Sound off in the comments below!

Join the conversation