London: Neil Patrick Harris, who acted with Britney Spears in an upcoming episode of the hit TV show "How I Met Your Mother", is all praise for the troubled pop star.

Contactmusic.com reports that Spears plays a secretary in a guest appearance on the show and Harris was impressed with her professionalism.

He said: "She is good. When we did the run through, she seemed a little nervous and wore big sunglasses the whole time. I think that's a bit of a security blanket. But she seems very professional."

Harris added that he got a unique insight into her personal troubles by working with her so close.

He said: "Being up close to her, she seems like a very fragile, kind of complicated person. It must be very strange to live her life."