Surat Kecil untuk Tuhan is a 2017 Indonesian adventure drama film produced by Falcon Pictures. Based on the novel of the same name by Agnes Davonar, it was directed by Fajar Bustomi and produced by Frederica, written by Upi and Bustomi, with Andreas Sullivan co-directing. The film stars the ensemble cast including Bunga Citra Lestari, Joe Taslim, Lukman Sardi, Bima Azriel, Izzati Khansa, Rifnu Wikana, Ben Joshua, Maudy Koesnadi, Jeroen Lezer, Chew Kin Wah, Susan Bachtiar and Dorman Borisman. Set in the early 2000s, the story follows Anton (Azriel) and Angel (Khansa), the orphan siblings who were stuck in a syndication in which uses homeless children.

Following the release of My Stupid Boss, Upi began working on the project when the idea first started. She pitched the concept to Falcon to develop Surat Kecil untuk Tuhan, while the story is inspired by family films, like Lion and Frozen. Development for Surat Kecil untuk Tuhan lasted for six months, on an approximate 10 billion Rupiah budget, and the film faced production difficulties, including story changes.Surat Kecil untuk Tuhan was premiered on 20 June 2017, and was released in Indonesia on 25 June. The film earned 26,4 billion rupiah, finishing its theatrical run as the fifteenth highest-grossing Indonesian film of 2017. The film won Bandung Film Festival for Best Cinematography and AMI Award for Best Children's Album, respectively. It also nominated for Citra Award for Best Child Performance and Indonesian Choice Award for Movie of the Year.