Steven Tyler is rumoured to be engaged.

The star's long-term girlfriend Erin Brady was spotted wearing a huge diamond ring on her left hand over the weekend.

According to TMZ, sources close to the couple have confirmed it is an engagement ring.

The pair went to Maui for a tropical Christmas day together. It is not clear whether 63-year-old Steven proposed before or after the trip.

The couple have been together since 2006.

Before they began dating Erin had already witnessed Steven's famous womanising ways. She used to tour with Aerosmith as their accountant.

The 38-year-old had a unique way of dealing with his behaviour.

"I saw him, how he behaved badly, but I just said, Hey, listen, if you're going to play, I'm going to play. I just want to make that clear to you.' And he didn't really like it I don't think, when he was on the other side of that scenario," she told Oprah Winfrey in an interview with both her and Steven.

The American Idol judge has been married twice before.

In 1978 he wed Cyrinda Foxe, who he divorced in 1987. He then married clothing designer Teresa Barrick in 1988 and they split formally in 2006. He has also had a string high-profile romances, including a brief fling with model Bebe Buell. The pair had daughter Liv Tyler together.