Justin Timberlake called wife Jessica Biel a 'MILF' Credit: Ilya S. Savenok/Getty Images for 2016 Tribeca Film Festival

Justin Timberlake can't believe his luck! The happy dad of one shared a supercute new photograph of his baby son, Silas, and his stunning wife, Jessica Biel, via Instagram to celebrate Mother's Day on Sunday, May 8.

But while the photograph (which showed little Silas, 13 months, from behind only, the message "I Heart Mom" emblazoned on his backside) was adorable, it was Timberlake's hilarious message that really made Us smile.

"M.I.L.F. Alert!!!!" the cheeky former boy-band hunk captioned the photograph. "Happy Mother's Day to this AMAZING MOM AND WIFE. And, to all of the Mother's out there... You keep the World turning!! Hope every single one of you has an amazing day! –JT."

Biel took a moment to talk to Us about her son and her husband during an appearance at the Tiffany & Co. Blue Book Gala in New York City last month.

“He’s a ham! He’s a total ham!” she said, laughing, before adding that he's "crawling like a maniac."

The first-time parent also got candid when asked about whether she ever feels mommy guilt. “Oh, you mean like a minute ago!? And about 10 seconds ago. And just now!” Biel cracked. “I feel it all the time. It’s hard to find that balance, you know, between working and feeling like an independent person and like a woman again.”

Looks like the men in her life think she's getting it absolutely right.

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