"Britney Spears' career comeback" was almost becoming a myth before it finally started happening on Monday's night episode of "How I Met Your Mother," which surprisingly enough, scored the show's highest ratings ever.

While the warm welcome from the critics proved that even though she's been going through some pretty rough moments over the past year, Britney Spears is still able to stand still long enough to deliver a good and entertaining performance on camera,  the numbers now show that she's still a popular punch line.

Britney Spears' cameo role as Abby, a ditsy secretary to a dermatologist, Stella (played by "Scrubs" star Sarah Chalke) that one of the characters, Ted (Josh Radnor), is interested in, helped boost the sitcom by about 1 million viewers, Nielsen Media Research estimates showed.

"Mother" spiked to a series high 4.5 preliminary rating among adults 18-49, even as the rest of the CBS comedy lineup fell from last week's record-setting return to original episodes.

Around 10.6 million viewers, up from last week's 9.7 million, tuned in to watch Britney's long anticipated appearance, which also topped the pop star's disappointing routine at the MTV Video Music Awards (7.1 million) in September last year. "Mother" was also the fourth-highest-rated show of the evening, and CBS won the night (averaging 12.5 million, 4.4/11).

Marking the singer's first major gig since the VMAs, Britney definitely seemed all right, as natural as her part allowed and focused on acting her best.

"She did pretty good" playing the hot yet dorky receptionist who develops a crush on Ted, Charna Halpern, artistic director of Chicago’s Improv Olympic Comedy Club, was quoted by Usmagazine.com as saying, "There was a sweetness to her, a vulnerability."

"She looked beautiful and had screen presence," added Halpern, who has trained such comedians as Tina Fey. "Even when she was behind the desk and they made her look kind of homely, she was adorable."

Her comedic timing "was good at some parts, especially in some of her reactions," Dean Cudworth, director of the Idol Camp, said.

Britney performed especially well in the scene where she handed Ted the embarrassing self-help book he was reading when he entered the lobby because "she was relaxed," Cudworth explained, "She was listening to the other characters and played off their performances with ease."

Other critics were equally impressed, "Britney the Trainwreck showed how she can still be Britney the Performer," the Associated Press wrote while The Daily News stated that for "those who hang on every one of Britney's career moves, this bold casting decision worked out. Spears proved she can act every bit as well as she can sing, and with some of the nuances she brought to the character, you'd almost swear she'd been there before."

Britney started receiving positive remarks from the very beginning of her work on the show, with insiders praising her for her professional behavior on the set.

"She showed up on time, knew her lines, was a good comedian and was able to do improvs," Bruce Fretts, editor-at-large for TV Guide was quoted by ABC.com as saying. "The cast really liked her … the crew really liked her."

She also managed to make rather low-key appearances for the shooting, being accompanied only by her stylist and her parents, Jamie, who is currently her co-conservator, and Lynne Spears.

Britney might not be a fabulous actress, but she’s definitely not bad and she does comedy well. She could easily play an ongoing supporting role on a sitcom.

"This is a step in the right direction for her," TV Guide's Fretts said. "This is the first thing we have seen her do in a while that seems like a smart move … that she's in charge and that she's trying to do something positive for a change."