Just a year and a half after breaking off his engagement with tennis player Caroline Wozniacki, Irish golfer Rory McIlroy is once again engaged.

Following less than a year of dating, the Northern Irish golfer is set to tie the knot with girlfriend Erica Stoll.

The couple attended a Paddy Wallace Fund event in Belfast on Thursday, December 10, where 27-year-old Stoll was spotted with a new diamond on her ring finger.

McIlroy, 26, first spoke about their relationship with the Time of London in May 2015.

What a night.. @McIlroyRory with his beautiful fiancée at tonight's Paddy Wallace’s @PWAutismFund Charity event pic.twitter.com/xGqCFVkPSr

— Press Eye Ltd (@presseyephoto) December 10, 2015

"I am very happy in my love life. We haven't really been putting it out there," he said.

"She doesn't play golf, but she is involved with golf. I have known her for three years and we are good friends. She is from America, which is why I like to spend time in Palm Beach."

The world number three also suggested that the improvement in his love life was having a positive impact on his swing.

"The past six or seven months have been really nice. That part of my life is going great," he added.

"If everything off the golf course is good, it allows you to be better on it as well."

McIlroy made his first public appearance with Stoll in June when they were seen in the Royal County Down Golf Club although they had previously been seen together in April in Rochester, New York.

It is believed the pro-golfer may have popped the question during a recent trip to Paris.

Bonjour! #jesuisparis

A photo posted by Rory McIlroy (@rorymcilroy) on

A friend recently told the Belfast Telegraph, “I wouldn't be surprised if they do tie the knot. You know the saying ‘when you know, you know’ and I think Rory is there now.

“She's met his family too. His parents are very fond of her. And she gels well with everyone. You'd be hard pressed to find a better match.”

Stoll works in Championship Volunteer Operations at the PGA (Professional Golfers Association) of America, meeting McIlroy in 2012.

She is famously known for acquiring McIlroy a police escort at the 2012 Ryder Cup to save him from missing his tee time when he was nowhere to be found on the site.

The County Down native broke off his previous engagement in May 2014, three days after the couple sent out their wedding invitations. Wozniacki has since stated that McIlroy ended the relationship via a ten-minute phone call. Meeting in 2011, they were together for two years.

McIlroy said at the time, "The problem is mine. The wedding invitations issued at the weekend made me realize that I wasn't ready for all that marriage entails.

“I wish Caroline all the happiness she deserves and thank her for the great times we've had. I will not be saying anything more about our relationship in any setting."