Katy Perry celebrated her 28th birthday by having lunch with Michelle Obama.

The Firework singer turned 28 yesterday (25 October) and says it will be a birthday she will always remember because she met with the US First Lady, while her husband President Obama, gave a ''shout out'' to her and her grandma.

She tweeted: ''So tonight was a great night! The PRESIDENT gave grandma and I unforgettable shout outs & now I am officially 28! Best. birthday. ever.''

She then followed up with: ''NOW my bday is complete! Lunch with @MichelleObama #chicvote''

Instead of presents, Katy asked for donations to be made to The David Lynch Foundation, a non-profit organisation transforming the lives of at-risk populations through meditation.

She retweeted her friend David Lynch: ''OMG! RT @DAVID_LYNCH: Dear Twitter Friends! It's @katyperry 's birthday & she requested donations to the @LynchFoundation in lieu of gifts.''

Katy - who is currently dating John Mayer - also took to her twitter to express her thanks at the birthday messages she had received and said they left her feeling very emotional.

She wrote: ''Thank you all for making me feel so special today. I'm overwhelmed with all the love that I might have a small happy cry now. So blessed.''