Earlier this month, former England footballer Frank Lampard and Northern Irish presenter Christine Bleakley (36) were spotted laughing and joking together over an al fresco lunch in London. On Christine's left hand, she proudly wore her engagement ring: a large solitaire stone flanked by smaller diamonds which is said to be worth in the region of €150,000.
It is now some three-and-a-half years since Frank got down on one knee on a beach in California and asked his then girlfriend of 18 months to marry him. This summer, the Dancing On Ice presenter was adamant that "the wedding plans are all good, in spite of what everyone keeps saying".
However, with her 36-year-old fiancé signing for New York City FC - he will shortly move Stateside for the US playing season, while Christine will stay behind in London - it seems unlikely that schedules will permit them to tie the knot in 2015.
Rena Maycock runs the successful Intro Matchmaking agency. She says there are numerous reasons why some people baulk at the idea of taking the final plunge into marriage - even when they're happily engaged.
"Men and women can like the idea of being engaged - that's still sexy in a way," she explains. "But maybe they then view marriage as being the opposite: full of responsibilities and chores. So they put it on the long finger. They try to buy themselves more time - another year here; another year there."
She adds: "The thought of actually exchanging vows can be overwhelming - it's easy to push it down the list of priorities."
And it seems the celebrity world is full of long, lingering engagements - famous faces who are happy to delay their big day...
Virginia Macari (39) and Kaste Dahl (44).
The Dublin social scene favourites have been engaged since May 2012.
History: They met in Marbella in 2009 and got engaged in May 2012. They have a two-and-a-half year old son, Thor, and recently relocated to Spain.
Plans: "We have finally set a date; it will be spring 2014," Virginia gushed 18 months ago. Sadly however, the nuptials are currently on ice as Kaste faces fraud charges in his native Norway.
Future: "Family stuff makes you realise that there are more important things in life," Virginia reflected recently.
Amy Adams (39) and Darren Le Gallo (40).
The Oscar-nominated star has been engaged to artist Darren since July 2008.
History: The pair first met in 2001 when they enrolled in the same acting class. They embarked on a relationship in 2002, with Darren popping the question in 2008. Four years ago, they welcomed their daughter, Aviana.
Plans: "I want something very family-oriented and laid back," Amy said recently of her ideal wedding day.
Future: "I'm not getting married anytime soon," Amy declared a year ago.
Actors Jennifer Aniston (45) and Justin Theroux (43).
They have been engaged since August 2012.
History: He was in a 14-year relationship with stylist Heidi Bivens. She was, of course, married to Brad Pitt. The pair met on the set of Wanderlust in 2011, and were engaged a year later.
Plans: The latest rumour is that the couple plan to elope in Fiji - but Jen has dismissed the idea absolutely.
Future: Reportedly, 81-year-old John Aniston is furious that Theroux still hasn't made an honest woman of his daughter. "I am not going to let a tabloid tell me what to do," Theroux has nevertheless declared.
Actress Kate Hudson (35) and Muse musician Matthew Bellamy (36).
They have been engaged since April 2011 and have a toddler son, Bing.
History: Kate and Matt met in the spring of 2010 at California's famed Coachella music festival. They now divide their time between LA and London.
Plans: "I am planning nothing right now because we've been so busy - and it's great," Kate has declared.
Future: In January it was rumoured that the pair were about to split. Apparently disagreements about where to live were at the forefront of their problems - but they appear to be very much back on track now.
Model Alessandra Ambrosio (33) and clothing entepreneur Jamie Mazur (44).
They have two children and have been engaged since August 2008.
History: They've been together for close to a decade. A daughter, Anja, was born in 2008, while their son, Noah, arrived in 2012.
Plans: "Right now I'm just concentrating on work and hanging out with my baby," she said shortly after Jamie asked her to marry him. Since then, talk of their nuptials has been scant.
Future: Early last year, it was thought that the pair had opted for a trial separation, though her representatives denied the rumour. More recently, Alessandra said of Jamie, "he makes me smile every day".