Mandal N. Picture: Instagram

"Lockdown" star Zola Nombona’s birthday tribute to actor and TV producer Mandla Ngcongwane aka Mandla N fuelled romance rumours.

Taking to her Instagram on Tuesday, Nombona who plays Monde on the award-winning female prison drama series, paid a heartfelt tribute to the show’s director and writer Mandla N. 

She wrote: “Happy birthday King. I genuinely have no words but I know you know how much I love and appreciate you. 

"May the Lord keep filling your cup and may he grant you all your hearts desires. Love you @mandla_n.”

To which Mandla replied: “Ou thanks a mil babe. Well done u killed it yesterday. Hola.”

But tweeps thought there is more than meets the eye, as speculations of the duo dating starting making rounds on social.

Twitter user @TinahH posted a screenshot of the IG, with the caption “Kanti isn’t he married?”

Tweeps starting drawing their own conclusions, with some alleging that the duo has been dating for some time now.

Industry friends including radio personality and entrepreneur DJ Sbu, Our Perfect Wedding host and actress Nomsa Buthelezi and "Love Live Here" star Lungile Radu took to social media to wish Mandla well on his special day.

"Happy birthday brother. I wish you many more💯💯💯🇿🇦🇿🇦," shared DJ Sbu.

Lungile Radu also commented: "Happy born day buddy @mandla_n blessings on blessings".

Taking to Instagram, the Gomorrah diva wrote: "HAPPY BIRTHDAY @mandla_n My director ... I remember I walked into the auditions of Abomzala Broke😳😳 but with so much to give and BUT YOU Believed in me Ngiyabonga and keep shinning !!!"

"Lockdown" Season 4 premiered on Mzansi Magic, on Monday, April 8.