Her Team GB swimmer grandson features in her header photo on Twitter. In her Twitter bio, it says "Proud Nan to a World Champion Breaststroker". And she's labelled herself the #OlympicNan.
We think we've just found Olympic gold medal hopeful Adam Peaty's absolute biggest fan: yes, his Nan. Awww.
"Love NaN" - oh, we can't cope.
Mavis Williams, who's from Sheffield, may not be in Rio herself - but her adorable and unwavering Twitter support is certainly making up for that.
Speaking to BBC Radio 5 live, Mavis said she wished she was in Rio to see him in action, but that hearing from her daughter Caroline and her husband Mark who are out there "brought a lump to my throat".
And it's not just Adam she's proud of. Oh no, other Team GB swimmers are getting Twitter mentions too.
Can we just say Mavis that we are particularly loving the emoji use. *claps*
She also told BBC Radio 5 live: "I am watching at home. Last night I was on my own and I still screamed for him but my neighbour didn't mind.
"Since I have been going to watch Adam it's given me a new life, a different life, that I never dreamt that I would have and I have loved every minute of it. I can't wait for tonight.
"I am really nervous but really excited too, not just for me but Adam - he has got a lot of pressure.
"He has achieved so much these last few years. It is a tremendous achievement, what he has got, and all the family are very proud of him. But it's nerve-racking for me."
Mavis added that Adam knows how proud she is of him because of the posts on Twitter.
And the proud nan will not be on her own when she watches her grandson go for gold tonight, saying: "I have got two people coming to me, so hopefully it will be a nice night."
Well, we can't wait to see the tweets about it.