Britney Spears's bedroom scenes with Neil Patrick Harris

In the episode Britney reprised her role as Abby, who dates serial womanizer Barney (Harris) but she still seems to be longing for her other crush, Ted (Josh Radnor).

The 26-year-old first appeared on the show in March.

The show's co-creator, Craig Thomas, said the episode was written to leave the door open for her to make a return appearance next season.

"She was better than the first time," he said, "and I think fans will enjoy it because her return answers a mystery set up earlier in the series."

Britney said in a statement: "I had such a great experience the last time I was on the show that I couldn't wait to come back."

"Abby is going to have a lot of fun!"