Spears 'won't be a regular on US sitcom'

How I Met Your Mother star Neil Patrick Harris has dismissed rumours that Britney Spears may become a regular on the show.

The singer filmed a guest spot as doctor's receptionist Abby on the hit CBS sitcom last month.

Her performance was praised by critics and earned ratings of 10.6 million, an increase of almost 2 million on the show's season average.

It was later reported that she was in talks to reprise her role and executive producer Carter Bays said she was welcome to return.

But Harris, who has played womaniser Barney since 2005, denied that she is in line for a permanent role.

He said: "They are totally unfounded rumours. She's not an actress. She played a role for a week, and did a really nice job, but the workload involved with doing memorization and the purging of comedy over and over is really, really hard.

"I mean, it takes a strong skill set to do that every week. You do it one week, it's fine, but to do it a lot of weeks is hard. She is not going to be a regular on our show."

He added that he was against the idea of casting celebrities in general, saying: "I'm in the minority [in thinking] that our show does not need stunt casting in order to succeed. I worry that if they start Will and Grace-ing us too much, the show will suffer."