The first rumors about actress Lindsay Lohan joining the cast of ABC's "Ugly Betty" surfaced months ago but slowly died down until last week when new reports emerged claiming the starlet was in talks with the show's producers.

And it seems a deal was reached because the 21-year-old star was spotted on the set of the sitcom in Los Angeles on Saturday. She will reportedly be featured on the show's season finale airing May 22. Although details about her part are scarce, Lindsay is set to play a former high school friend of America Ferrera's character, Betty, who didn't use to treat Betty very well.

According to Variety.com, the actress, who was in rehab three times in 2007, will also appear in five more episodes of the upcoming season of "Ugly Betty." TVGuide.com claimed that Lohan could in fact be lining up as many as eight episodes of the show.

Earlier last week, supermodel Naomi Campbell was also spotted on the set of the show shooting her scenes for the upcoming second series finale episode. The catwalk queen plays "a loony who loves to shop and can't find a man." Campbell, who was taught how to play softball, will be seen taking part in a match that pitches a team of models against the show's regular cast.

"I was given a crash course in playing softball and at one point hit the ball so hard it actually broke in half!" Campbell said, adding that she "had a fantastic day on set, the cast and crew were lovely," unlike the people she usually gets angry with.

Victoria Beckham has also had a cameo on the show, playing a bridesmaid to Vanessa Williams' catty fashion boss character, Wilhelmina Slater, in November last year.