Mischa Barton has sparked speculation she is engaged.

The actress has been dating actor Sebastian Knapp for several months. Yesterday, she was spotted out and about in Dublin, Ireland, with a stunning diamond ring on her engagement finger.

The 26-year-old star was on her way to a party to celebrate the play Steel Magnolias and didn't bother trying to hide the band.

The actress was wearing dark blue jeans and a simple tan sweater. Her left hand was reaching across her body towards her bag strap, giving photographers a clear view of the gem.

Mischa's romance with Sebastian came just weeks after she insisted she wasn't interested in a relationship.

"I've given up men. Sadly, there doesn't seem to be anyone out there for me," she told British newspaper The Daily Mail.

"My last three boyfriends haven't worked out, so I'm giving guys a rest for a while."

The pair met at the wedding of actress Ashley Madekwe, who is friends with Mischa, in June.