Lindsay Lohan's performance on the set of U.s. TV show Ugly Betty has impressed the series' star America Ferrera.

Lohan is set to appear on the show's season finale next week to play Kimberley, the high school nemesis of Ferrera's title character Betty.

The 21-year-old actress signed up for six episodes of the hit program in a bid to reignite her struggling Hollywood career.

And Ferrera, 24, is keen to join the chorus of Ugly Betty bosses who claim Lohan's reputation as a troublesome and tardy star is unfounded.

Ferrera coos, "(Lohan) was really wonderful and was gracious and showed up and was on time."

"I don't mean to be smart or snide. She was really great, she was lovely. She's going to be back for five more episodes in the third season here in New York."