The return of three hits - Grey's Anatomy, Lost and Ugly Betty - to ABC's Thursday night lineup has made scheduling a bit tricky for the network.

Especially regarding the season finales of each.

The network's original plan was for the two-part Lost finale to air over two nights, and have all three shows end on the same evening, May 22.

However, sources confirm that the Lost finale has been rescheduled, making room for a two-hour Grey's Anatomy season finale.

ABC's changes to the final weeks of its Thursday lineup:

• On May 15, Part I of the Lost finale will follow new episodes of Grey's Anatomy (9 p.m.) and Ugly Betty. Nothing new.
• There will be no Lost on May 22. The Ugly Betty finale (8 p.m.) and the new, two-hour Grey's Anatomy finale will air instead.
• On May 29, ABC has scheduled an encore of Part I of the Lost finale, followed by the two-hour, second installment of it.

So, that extra hour to close the tumultuous Season Four on May 22 is like another full episode of Grey's Anatomy if you want to look at it that way!

The first episode back, "Where the Wild Things Are," is set for April 24 (not that we have a countdown going on here or anything). "Piece of My Heart" will air May 1, and "The Becoming" is scheduled for May 8. That leaves us with one more (currently unnamed) Grey's Anatomy episode for May 15 and then the two-part finale.

For a look at what's to come, check out our Grey's Anatomy spoiler section!

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.