Nikki Bella has belatedly congratulated John Cena after his wedding.

Nikki Bella

Nikki Bella

The 'Total Bellas' star admitted she hadn't spoken to her ex-fiance after he married Shay Shariatzadeh in October, as she joked about whether there are "rules" regarding wishing a former flame well in this situation.

Responding to a fan-submitted question on the 'All Things Vanderpump' podcast, she said: "I haven't [congratulated him]... but yeah, I didn't.

"Are there rules? Am I supposed to? Should I send flowers?"

Nikki's twin sister Brie - who married WWE superstar Daniel Bryan in 2014 - insisted she didn't reach out to an ex when he tied the knot.

She added: "We were done for so long that I didn't congratulate him, but he didn't congratulate me."

Host Lisa Vanderpump suggested to Nikki she should "get out of this really elegantly" by sending wrestler-turned-actor John a sweet message after his recent nuptials.

She replied: "John, congratulations on your wedding. I’m very, very happy for you.”

Nikki recently admitted John - whom she started dating in 2012 before getting engaged in 2017 and splitting the following year - got in touch with her and Brie after they both gave birth earlier this year.

The 36-year-old reality star and her partner Artem Chingvintsev welcomed son Matteo into the world in July, just a day before her sister Brie Bella gave birth to her second child, Buddy.

She said: "With the baby, he reached out to Brie and I both. We haven’t had an individual conversation in gosh, I don’t know how long, but it was very short and sweet!”

Meanwhile, in November 2019, John admitted he was "extremely happy" in his relationship with Shay, who was born in Iran and is a Canadian citizen.

Although keeping coy about his romance at the time, he said: "I can say with great confidence I'm extremely happy. I always try and give you a little something."