Britney Spears to return to How I Met Your Mother

Britney Spears is set to return to How I Met Your Mother.

"The show is ecstatic and so is Britney," a source tells People.com. "She had so much fun the first time around she really wanted to come back. It was a mutual decision to work together more."

The Toxic star, 26, will do just the one episode, the source says. Fox studios would not confirm the appearance.

The singer appeared on the March 24 episode, playing a a bubbly, sweet, receptionist at a dermatologist’s office who fell for one of the show’s main characters, played by Josh Radnor. She received wide accolades for the spot.

"She was hilarious in the table-read, and I got to see her do the run-through as well, and she was great," cast member Jason Segal said.

However, another How I Met Your Mother star -- Neil Patrick Harris -- recently said the CBS sitcom "does not need stunt casting [like Britney Spears] in order to succeed", adding, "I worry that if they start 'Will and Grace'-ing us too much, that the show will suffer.

"And we're all really proud of the content of the show. I mean, viewership is not our game," he said. "It's the network and the studio's game, you know. It's the promotion department's game."

Britney has been the most high-profile celebrity guest to visit the set, following past appearances by Mandy Moore, Enrique Iglesias and Heidi Klum.

Spears' cameo created so much buzz that 10.6 million viewers tuned into watch the episode -- roughly 2-million more than the sitcom -- which has grown a cult following since its 2005 debut -- averages per showing. Among the 18-49-year old demographic, it was the most-watched episode of the series ever.