The actress who co-created the popular comedy drama was presented with the award by the Queen during a Windsor Castle investiture ceremony.
Jones, who is busy filming the latest series of the Sky comedy Stella, said: "It's a huge honour and I feel really lucky, I love doing my job. I suppose doing the job you love is reward enough but this is like the icing on the cake.
"It's funny, yesterday I was on the film set as Stella, which we're filming at the moment, and I was dressed up in my nurse's costume, with my wig on shouting at somebody and today I'm in Windsor Castle getting an MBE - so life is very rich and varied, let's put it that way."
The actress and writer got her big break on ITV's diet club drama Fat Friends in 2000 and more importantly also met co-star James Corden.
The pair came up with the idea for Gavin & Stacey during breaks from filming and the show, set partly in her native South Wales, became a massive hit.
The award-winning comedy was a huge critical and commercial hit and made Jones, who co-wrote it and played the larger-than-life Nessa, a star.
Other roles include playing Carry On star Hattie Jacques in a BBC biopic.
The multi-talented Jones plays the title character in Stella but also co-wrote and produced the show, which is set in the South Wales valleys, with her husband, David Peet.
Jones, who was announced during the investiture by her married name Ruth Peet, said: "It feels weird talking about Gavin & Stacey because it was such a long time ago but it was a huge part of my life, I had such a great time, I loved working with James Corden.
"But things move on, we're on our fourth series of Stella now.
"I do have a laugh doing my job and I work with my husband, we have a production company, so it's great we're able to spend time together working.
"I am a bit of a perfectionist and I do tend to throw myself into things quite a lot - I want it to be as good as it can be."
Speaking about her brief chat with the Queen during the MBE presentation, the actress added: "I told her that I write and perform and she said to me 'that sounds like an immense amount of fun'."
She added, laughing: "I have no expectation whatsoever that the Queen has ever seen an episode of Gavin & Stacey or Stella. I think we sent Prince Charles a boxset of Gavin & Stacey once and I think William and Harry like it."