You'd think Britney Spears' fans would be the kindest about what was billed as the pop singer's comeback performance at the MTV Video Music Awards Sunday.

However, it appears that they hated it, too.

During the performance, which started the VMA program, Spears appeared to be lip-synching and sometimes seemed unprepared -- and celebrities in the audience looked confused.

Fans writing on the fan site WorldOfBritney.com at best called it "sad" and at worst called Spears "a clown."

Several fans bypassed critiquing Spears' performance in favor of ripping on VMA host Sarah Silverman, who cracked jokes at Spears' expense immediately afterwards.

In her opening monologue, Silverman said Spears is amazing because "she is 25 years old and she's already accomplished everything she's going to accomplish in her life."

The comedian also called Spears' children "the most adorable mistakes."

One fan said Spears' performance "sealed the deal for the end of her career," while others said Spears should give up on show biz for a while and focus on her family.

Several fans ripped on Spears for dressing like a teenager when she's a mom now.

The critical comments about Spears weren't limited to fans on the Web. The New York Post poked fun at Spears' weight with the headline, "Lard and Clear."

Meanwhile, it's possible Spears' opening shot may not even make MTV's "remix" show on Thursday.

Spears is not in the top 20 of performances, moments or overall clips, as voted by viewers on MTV.com.

Chris Brown's "Wall to Wall" performance leads the voting so far.