Spears having a 'blast' on US sitcom

Britney Spears is having a "blast" on the set of US sitcom How I Met Your Mother.

The singer has been recording her guest spot as doctor's receptionist Abby on the CBS show.

She said in a statement: "Working at How I Met Your Mother has been so terrific. Everyone, including the cast, the crew and the producers, has been wonderful and Abby is such a fun girl to play. I'm having a blast!"

A CBS spokesman said she attended a table reading for the episode on Monday, completed a "run-through" on Tuesday, and filmed scenes on Wednesday and Thursday.

Co-star Josh Radnor (Ted) praised Spears's professional attitude on set, telling People: "On the first day of the shoot, Britney knew her lines better than I knew mine. She's been great to work with."

Neil Patrick Harris, who plays womanizer Barney, told E!: "It's an interesting change of pace for her to be around a group of people that don't have an agenda with her or want to take her picture."

The episode is expected to air in the US on March 24.

Alicia Silverstone has denied claims that she pulled out of a cameo as a doctor after learning she would be starring with Spears.