A man has tragically drowned while proposing to his girlfriend underwater during a dream holiday in Tanzania.

Steven Weber Jr. died minutes after he asked his girlfriend Kenesha Antoine to marry him this week.

The circumstances of his death are unclear but Kenesha took to Facebook on Friday to announce his death and explain she never had the chance to tell him yes.

In an emotional post that includes a video of the proposal and photos of the American couple, she said: "There are no words adequate enough to honour the beautiful soul that is Steven Weber, Jr.

"You were a bright light to everyone you encountered.

"You never emerged from those depths, so you never got to hear my answer, “Yes! Yes! A million times, yes, I will marry you!!"."

The video shows Steven swimming underwater and holding a zipper storage bag with a handwritten note inside.

One side reads: "I can't hold my breath long enough to tell you everything I love about you.

"But everything I love about you I love more every day!'"

He then shows the other side where he asks Kenesha to marry him before producing a ring.

Kenesha, an attorney, is heard laughing in the background.

Paying tribute to her late partner, Kenesha also wrote: "Just a couple days before you died, you said to me, “I’ve seen a few cancer patients on this trip, and it dawned on me that this is a once-in-a-lifetime thing that people want to experience before they die.

"And here we are in the prime of our lives doing this. We are so blessed.

"Yes, we were, my perfect love, my angel, my soul.

"Yes, we were, and I will carry the blessing of the love we shared with me forever.

"I will find you and marry you in the next lifetime, and the next, and the next, and the next... I love you so much, and I always will."

The post has been liked more than 1,700 times with friends and strangers offering their condolences.

One said: "Steven is the truest friend one can ever know and love.

"My deepest condolences to you, I can’t express how much my and this world lost with this news.

"Thank you for being an angel with him, this is still impossible to comprehend.

Another posted: "I don’t know you guys but you will be in my thoughts in prayers and from the pictures he was an amazing person and loved you very much!!

"I pray you find comfort and peace!

"He will always be a part of you! My condolences to you and the entire family."

According to Steven's Facebook page, he worked at an addiction centre in Lousiana.

The US State Department is reportedly aware of Steven's death.