03/06/2012 02:59 pm ET Updated May 06, 2012

'Downton Abbey': Maggie Smith, Dan Stevens Not Confirmed For Season 4 And Season 5

Is there trouble ahead for PBS' hit period drama "Downton Abbey?" According to UK tabloid The Mirror, the show's feisty Dowager Countess, played by Dame Maggie Smith, and the "Abbey's" resident heartthrob Matt Crawley may not be returning to the estate for Seasons 4 and 5.

The paper reports that Smith is considering her future on the Golden Globe-winning period drama. The Mirror has confirmed that Smith has yet to sign on or even enter negotiations for future seasons of "Downton" after Season 3.

TV Line recently reported that most of the principal cast of the small screen phenomenon "Downton Abbey" have signed new contracts to star in both Seasons 4 and 5: Michelle Dockery (Lady Mary), Elizabeth McGovern (Cora), Hugh Bonneville (Robert), Joanne Froggatt (Anna) and Brendan Coyle (Bates) are among the returning cast members.

However, Siobhan Finneran, who stars as wicked housekeeper Miss O'Brien, and Jessica Brown Findlay, who plays Lady Sybil Branson, have yet to sign on for future seasons as well.

ITV has yet to commission Seasons 4 and 5, which may have something to do with why Smith and Stevens are holding off on contract negotiations.

"Downton Abbey" Season 3 is currently in production in the UK, where American actress Shirley MacLaine is guest starring as Lady Crawley's mother.