Things Get 'Ugly' (On Screen) for Lindsay

Promises? What's that? In further proof that guest-starring on a sitcom is the new version of image rehab, Lindsay Lohan has signed to appear in six episodes of ABC's Ugly Betty. She plays an old high school rival of Betty's in the May 22 finale (complete with a requisite mortifying dodgeball flashback), and she'll return for five episodes next fall. Considering that CBS' How I Met Your Mother earned its biggest audience of the season when Britney punched in a few weeks back — and that Betty is suffering a 15 percent year-to-year dip in ratings — could La Lohan's arrival be less about pushing the story forward and more about juicing the ratings? ''Hopefully it will help,'' admits exec producer Silvio Horta, who's already welcomed Victoria Beckham, Gene Simmons, and Project Runway winner Christian Siriano this season. ''But we only want to have a guest star if it's a really good thing for the show. We're high-class call girls. We're never gonna have Paris Hilton.''