Lindsay Lohan has impressed the cast and crew on the set of Ugly Betty with her surprisingly professional behaviour.

The actress – whose past form has shown a laid back attitude to showing up for work – apparently turned up a whole 45 minutes EARLY to film her guest spot on the ABC show.

"She was terrific - a pleasure," Ugly Betty creator Silvio Horta told Usmagazine.com.

"She came in early and was very pleasant."

Praise, indeed.
 
Lindsay will appear in flashback scene in the May 22 season finale playing Kimberly - "a queen bee girl who Betty went to high school with," says Horta.

The Mean Girls star will also be returning for five more episodes next season.

"They're going to run into each other," says Horta. "Kimberly's life has taken a turn for the worst."

Can Lindsay keep up the good behaviour?