Heidi Klum & Seal Celebrate Johan’s 3rd Birthday!

Over the weekend, approximately fifty guests made their way to the home of Heidi Klum and husband Seal to celebrate their son Johan’s third birthday!

The party was train-themed and the two proud parents dressed in overalls and conductor hats along with their other three children – Leni, 5, Henry, 4, and 6-week-old baby Lou.

“They really got into the spirit of the whole train theme,” a source tells PEOPLE. “They always have so much fun together as a family.”

The couple’s LA home was decorated with red, blue, green and yellow balloons and a clown was there to entertain the kids. The guests also got to take a ride on a miniature train that was set up in the backyard.

Happy birthday, Johan!