Britney Spears is yet to sign on the dotted line for another episode of How I Met Your Mother, despite reports she's all set to return to the hit U.S. sitcom.

According to a U.S publication, the singer has agreed to appear in one more episode of the show following her successful cameo appearance last month.

However, an insider tells Us, "Nothing is signed yet.”

“No script has been written and until that is done, Britney will not be making a commitment. The offer is there but no decisions have been made at the moment."

Britney received rave reviews for her comic turn in the March 24 episode of the CBS comedy, in which she played a love-struck receptionist at a dermatologist’s office.

Meanwhile, How I Met Your Mother star Neil Patrick Harris has been busy back-peddling after commenting recently that the CBS sitcom "does not need stunt casting to succeed."

He has since told Extra, "...we would be so lucky to have [Britney]. She was great fun the first time.”