WASHINGTON (AFP) - After an art history professor took offence at a comment he made last month, US President Barack Obama sought to make amends - with a handwritten note of apology.

Last month, Mr Obama - speaking on the economy at a factory in Wisconsin - said "folks can make a lot more, potentially, with skilled manufacturing or the trades than they might with an art history degree".

The US leader immediately added, to laughter from the crowd: "Now, nothing wrong with an art history degree - I love art history. So I don't want to get a bunch of e-mails from everybody."

But art history professor Ann Collins Johns at the University of Texas in Austin did feel insulted, and she registered her protest via the White House website.

She got the shock of her life several days later - a response from the commander-in-chief himself.

"Let me apologise for my off-the-cuff remarks. I was making a point about the jobs market, not the value of art history," read the letter.

"As it so happens, art history was one of my favourite subjects in high school," it added.

The White House sent Professor Johns a scan of the handwritten note via e-mail, with the original to follow by regular post.

A copy of Mr Obama's note was published on the arts blog hyperallergic.com

Contacted by Agence France-Presse, the White House did not dispute the authenticity of the note, but did not offer additional comment.

Prof Johns said she was very surprised to get such a response from a President she already admired.

"So now I'm totally guilty about wasting his time," she said, according to the blog.